annotate Doc/lib/libstdtypes.tex @ 24459:189eb6fa9ded legacy-trunk

Added new footnote about list.sort() stability. Repaired footnote about using sort() with comparison functions (it made reference to the non- existent "builtin-in function sort()"). BTW, I changed list.sort's docstring to contain the word "stable" -- the easiest way to tell whether a particular Python version's sort *is* stable is to look for "stable" in the docstring. I'm not sure whether to advertise this <wink>.
author Tim Peters <tim.peters@gmail.com>
date Thu, 01 Aug 2002 03:10:45 +0000
parents 62f4b45b05fd
children 12e146171f3d
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
1 \section{Built-in Types \label{types}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
2
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
3 The following sections describe the standard types that are built into
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
4 the interpreter. Historically, Python's built-in types have differed
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
5 from user-defined types because it was not possible to use the built-in
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
6 types as the basis for object-oriented inheritance. With the 2.2
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
7 release this situation has started to change, although the intended
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
8 unification of user-defined and built-in types is as yet far from
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
9 complete.
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
10
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
11 The principal built-in types are numerics, sequences, mappings, files
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
12 classes, instances and exceptions.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
13 \indexii{built-in}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
14
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
15 Some operations are supported by several object types; in particular,
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
16 all objects can be compared, tested for truth value, and converted to
9558
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
17 a string (with the \code{`\textrm{\ldots}`} notation). The latter
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
18 conversion is implicitly used when an object is written by the
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
19 \keyword{print}\stindex{print} statement.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
20
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
21
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
22 \subsection{Truth Value Testing} \label{truth}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
23
9558
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
24 Any object can be tested for truth value, for use in an \keyword{if} or
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
25 \keyword{while} condition or as operand of the Boolean operations below.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
26 The following values are considered false:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
27 \stindex{if}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
28 \stindex{while}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
29 \indexii{truth}{value}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
30 \indexii{Boolean}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
31 \index{false}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
32
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
33 \begin{itemize}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
34
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
35 \item \code{None}
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
36 \withsubitem{(Built-in object)}{\ttindex{None}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
37
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
38 \item \code{False}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
39 \withsubitem{(Built-in object)}{\ttindex{False}}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
40
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
41 \item zero of any numeric type, for example, \code{0}, \code{0L},
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
42 \code{0.0}, \code{0j}.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
43
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
44 \item any empty sequence, for example, \code{''}, \code{()}, \code{[]}.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
45
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
46 \item any empty mapping, for example, \code{\{\}}.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
47
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
48 \item instances of user-defined classes, if the class defines a
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
49 \method{__nonzero__()} or \method{__len__()} method, when that
24227
8a67f28a42a5 Clarify the return value of __nonzero__(): It *must* be an integer.
Fred Drake <fdrake@acm.org>
parents: 23860
diff changeset
50 method returns the integer zero.\footnote{Additional
8a67f28a42a5 Clarify the return value of __nonzero__(): It *must* be an integer.
Fred Drake <fdrake@acm.org>
parents: 23860
diff changeset
51 information on these special methods may be found in the
8a67f28a42a5 Clarify the return value of __nonzero__(): It *must* be an integer.
Fred Drake <fdrake@acm.org>
parents: 23860
diff changeset
52 \citetitle[../ref/ref.html]{Python Reference Manual}.}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
53
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
54 \end{itemize}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
55
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
56 All other values are considered true --- so objects of many types are
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
57 always true.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
58 \index{true}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
59
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
60 Operations and built-in functions that have a Boolean result always
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
61 return \code{0} or \code{False} for false and \code{1} or \code{True}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
62 for true, unless otherwise stated. (Important exception: the Boolean
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
63 operations \samp{or}\opindex{or} and \samp{and}\opindex{and} always
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
64 return one of their operands.)
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
65 \index{False}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
66 \index{True}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
67
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
68 \subsection{Boolean Operations \label{boolean}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
69
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
70 These are the Boolean operations, ordered by ascending priority:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
71 \indexii{Boolean}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
72
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
73 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
74 \lineiii{\var{x} or \var{y}}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
75 {if \var{x} is false, then \var{y}, else \var{x}}{(1)}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
76 \lineiii{\var{x} and \var{y}}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
77 {if \var{x} is false, then \var{x}, else \var{y}}{(1)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
78 \hline
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
79 \lineiii{not \var{x}}
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
80 {if \var{x} is false, then \code{True}, else \code{False}}{(2)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
81 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
82 \opindex{and}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
83 \opindex{or}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
84 \opindex{not}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
85
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
86 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
87 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
88
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
89 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
90
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
91 \item[(1)]
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
92 These only evaluate their second argument if needed for their outcome.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
93
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
94 \item[(2)]
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
95 \samp{not} has a lower priority than non-Boolean operators, so
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
96 \code{not \var{a} == \var{b}} is interpreted as \code{not (\var{a} ==
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
97 \var{b})}, and \code{\var{a} == not \var{b}} is a syntax error.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
98
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
99 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
100
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
101
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
102 \subsection{Comparisons \label{comparisons}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
103
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
104 Comparison operations are supported by all objects. They all have the
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
105 same priority (which is higher than that of the Boolean operations).
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
106 Comparisons can be chained arbitrarily; for example, \code{\var{x} <
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
107 \var{y} <= \var{z}} is equivalent to \code{\var{x} < \var{y} and
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
108 \var{y} <= \var{z}}, except that \var{y} is evaluated only once (but
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
109 in both cases \var{z} is not evaluated at all when \code{\var{x} <
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
110 \var{y}} is found to be false).
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
111 \indexii{chaining}{comparisons}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
112
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
113 This table summarizes the comparison operations:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
114
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
115 \begin{tableiii}{c|l|c}{code}{Operation}{Meaning}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
116 \lineiii{<}{strictly less than}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
117 \lineiii{<=}{less than or equal}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
118 \lineiii{>}{strictly greater than}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
119 \lineiii{>=}{greater than or equal}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
120 \lineiii{==}{equal}{}
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
121 \lineiii{!=}{not equal}{(1)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
122 \lineiii{<>}{not equal}{(1)}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
123 \lineiii{is}{object identity}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
124 \lineiii{is not}{negated object identity}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
125 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
126 \indexii{operator}{comparison}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
127 \opindex{==} % XXX *All* others have funny characters < ! >
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
128 \opindex{is}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
129 \opindex{is not}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
130
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
131 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
132 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
133
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
134 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
135
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
136 \item[(1)]
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
137 \code{<>} and \code{!=} are alternate spellings for the same operator.
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
138 \code{!=} is the preferred spelling; \code{<>} is obsolescent.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
139
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
140 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
141
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
142 Objects of different types, except different numeric types, never
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
143 compare equal; such objects are ordered consistently but arbitrarily
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
144 (so that sorting a heterogeneous array yields a consistent result).
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
145 Furthermore, some types (for example, file objects) support only a
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
146 degenerate notion of comparison where any two objects of that type are
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
147 unequal. Again, such objects are ordered arbitrarily but
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
148 consistently. The \code{<}, \code{<=}, \code{>} and \code{>=}
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
149 operators will raise a \exception{TypeError} exception when any operand
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
150 is a complex number.
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
151 \indexii{object}{numeric}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
152 \indexii{objects}{comparing}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
153
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
154 Instances of a class normally compare as non-equal unless the class
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
155 \withsubitem{(instance method)}{\ttindex{__cmp__()}}
14485
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
156 defines the \method{__cmp__()} method. Refer to the
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
157 \citetitle[../ref/customization.html]{Python Reference Manual} for
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
158 information on the use of this method to effect object comparisons.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
159
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
160 \strong{Implementation note:} Objects of different types except
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
161 numbers are ordered by their type names; objects of the same types
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
162 that don't support proper comparison are ordered by their address.
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
163
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
164 Two more operations with the same syntactic priority,
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
165 \samp{in}\opindex{in} and \samp{not in}\opindex{not in}, are supported
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
166 only by sequence types (below).
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
167
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
168
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
169 \subsection{Numeric Types \label{typesnumeric}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
170
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
171 There are four distinct numeric types: \dfn{plain integers},
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
172 \dfn{long integers},
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
173 \dfn{floating point numbers}, and \dfn{complex numbers}.
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
174 In addition, Booleans are a subtype of plain integers.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
175 Plain integers (also just called \dfn{integers})
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
176 are implemented using \ctype{long} in C, which gives them at least 32
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
177 bits of precision. Long integers have unlimited precision. Floating
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
178 point numbers are implemented using \ctype{double} in C. All bets on
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
179 their precision are off unless you happen to know the machine you are
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
180 working with.
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
181 \obindex{numeric}
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
182 \obindex{Boolean}
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
183 \obindex{integer}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
184 \obindex{long integer}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
185 \obindex{floating point}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
186 \obindex{complex number}
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
187 \indexii{C}{language}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
188
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
189 Complex numbers have a real and imaginary part, which are each
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
190 implemented using \ctype{double} in C. To extract these parts from
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
191 a complex number \var{z}, use \code{\var{z}.real} and \code{\var{z}.imag}.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
192
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
193 Numbers are created by numeric literals or as the result of built-in
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
194 functions and operators. Unadorned integer literals (including hex
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
195 and octal numbers) yield plain integers unless the value they denote
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
196 is too large to be represented as a plain integer, in which case
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
197 they yield a long integer. Integer literals with an
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
198 \character{L} or \character{l} suffix yield long integers
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
199 (\character{L} is preferred because \samp{1l} looks too much like
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
200 eleven!). Numeric literals containing a decimal point or an exponent
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
201 sign yield floating point numbers. Appending \character{j} or
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
202 \character{J} to a numeric literal yields a complex number with a
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
203 zero real part. A complex numeric literal is the sum of a real and
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
204 an imaginary part.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
205 \indexii{numeric}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
206 \indexii{integer}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
207 \indexiii{long}{integer}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
208 \indexii{floating point}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
209 \indexii{complex number}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
210 \indexii{hexadecimal}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
211 \indexii{octal}{literals}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
212
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
213 Python fully supports mixed arithmetic: when a binary arithmetic
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
214 operator has operands of different numeric types, the operand with the
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
215 ``narrower'' type is widened to that of the other, where plain
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
216 integer is narrower than long integer is narrower than floating point is
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
217 narrower than complex.
10520
7ee1e3134147 Fixed latex2html weirdness with footnotes.
Fred Drake <fdrake@acm.org>
parents: 10241
diff changeset
218 Comparisons between numbers of mixed type use the same rule.\footnote{
7ee1e3134147 Fixed latex2html weirdness with footnotes.
Fred Drake <fdrake@acm.org>
parents: 10241
diff changeset
219 As a consequence, the list \code{[1, 2]} is considered equal
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
220 to \code{[1.0, 2.0]}, and similarly for tuples.
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
221 } The constructors \function{int()}, \function{long()}, \function{float()},
9558
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
222 and \function{complex()} can be used
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
223 to produce numbers of a specific type.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
224 \index{arithmetic}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
225 \bifuncindex{int}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
226 \bifuncindex{long}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
227 \bifuncindex{float}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
228 \bifuncindex{complex}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
229
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
230 All numeric types support the following operations, sorted by
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
231 ascending priority (operations in the same box have the same
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
232 priority; all numeric operations have a higher priority than
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
233 comparison operations):
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
234
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
235 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
236 \lineiii{\var{x} + \var{y}}{sum of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
237 \lineiii{\var{x} - \var{y}}{difference of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
238 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
239 \lineiii{\var{x} * \var{y}}{product of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
240 \lineiii{\var{x} / \var{y}}{quotient of \var{x} and \var{y}}{(1)}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
241 \lineiii{\var{x} \%{} \var{y}}{remainder of \code{\var{x} / \var{y}}}{}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
242 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
243 \lineiii{-\var{x}}{\var{x} negated}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
244 \lineiii{+\var{x}}{\var{x} unchanged}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
245 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
246 \lineiii{abs(\var{x})}{absolute value or magnitude of \var{x}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
247 \lineiii{int(\var{x})}{\var{x} converted to integer}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
248 \lineiii{long(\var{x})}{\var{x} converted to long integer}{(2)}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
249 \lineiii{float(\var{x})}{\var{x} converted to floating point}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
250 \lineiii{complex(\var{re},\var{im})}{a complex number with real part \var{re}, imaginary part \var{im}. \var{im} defaults to zero.}{}
10147
3ac7f0066375 Document <complex #>.conjugate().
Fred Drake <fdrake@acm.org>
parents: 9558
diff changeset
251 \lineiii{\var{c}.conjugate()}{conjugate of the complex number \var{c}}{}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
252 \lineiii{divmod(\var{x}, \var{y})}{the pair \code{(\var{x} / \var{y}, \var{x} \%{} \var{y})}}{(3)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
253 \lineiii{pow(\var{x}, \var{y})}{\var{x} to the power \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
254 \lineiii{\var{x} ** \var{y}}{\var{x} to the power \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
255 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
256 \indexiii{operations on}{numeric}{types}
10147
3ac7f0066375 Document <complex #>.conjugate().
Fred Drake <fdrake@acm.org>
parents: 9558
diff changeset
257 \withsubitem{(complex number method)}{\ttindex{conjugate()}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
258
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
259 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
260 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
261 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
262
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
263 \item[(1)]
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
264 For (plain or long) integer division, the result is an integer.
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
265 The result is always rounded towards minus infinity: 1/2 is 0,
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
266 (-1)/2 is -1, 1/(-2) is -1, and (-1)/(-2) is 0. Note that the result
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
267 is a long integer if either operand is a long integer, regardless of
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
268 the numeric value.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
269 \indexii{integer}{division}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
270 \indexiii{long}{integer}{division}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
271
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
272 \item[(2)]
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
273 Conversion from floating point to (long or plain) integer may round or
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
274 truncate as in C; see functions \function{floor()} and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
275 \function{ceil()} in the \refmodule{math}\refbimodindex{math} module
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
276 for well-defined conversions.
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
277 \withsubitem{(in module math)}{\ttindex{floor()}\ttindex{ceil()}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
278 \indexii{numeric}{conversions}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
279 \indexii{C}{language}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
280
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
281 \item[(3)]
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
282 See section \ref{built-in-funcs}, ``Built-in Functions,'' for a full
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
283 description.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
284
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
285 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
286 % XXXJH exceptions: overflow (when? what operations?) zerodivision
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
287
10241
f138ba72bf2d Update description of what modules "look like" when printed.
Fred Drake <fdrake@acm.org>
parents: 10156
diff changeset
288 \subsubsection{Bit-string Operations on Integer Types \label{bitstring-ops}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
289 \nodename{Bit-string Operations}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
290
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
291 Plain and long integer types support additional operations that make
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
292 sense only for bit-strings. Negative numbers are treated as their 2's
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
293 complement value (for long integers, this assumes a sufficiently large
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
294 number of bits that no overflow occurs during the operation).
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
295
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
296 The priorities of the binary bit-wise operations are all lower than
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
297 the numeric operations and higher than the comparisons; the unary
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
298 operation \samp{\~} has the same priority as the other unary numeric
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
299 operations (\samp{+} and \samp{-}).
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
300
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
301 This table lists the bit-string operations sorted in ascending
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
302 priority (operations in the same box have the same priority):
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
303
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
304 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
305 \lineiii{\var{x} | \var{y}}{bitwise \dfn{or} of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
306 \lineiii{\var{x} \^{} \var{y}}{bitwise \dfn{exclusive or} of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
307 \lineiii{\var{x} \&{} \var{y}}{bitwise \dfn{and} of \var{x} and \var{y}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
308 \lineiii{\var{x} << \var{n}}{\var{x} shifted left by \var{n} bits}{(1), (2)}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
309 \lineiii{\var{x} >> \var{n}}{\var{x} shifted right by \var{n} bits}{(1), (3)}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
310 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
311 \lineiii{\~\var{x}}{the bits of \var{x} inverted}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
312 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
313 \indexiii{operations on}{integer}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
314 \indexii{bit-string}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
315 \indexii{shifting}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
316 \indexii{masking}{operations}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
317
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
318 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
319 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
320 \begin{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
321 \item[(1)] Negative shift counts are illegal and cause a
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
322 \exception{ValueError} to be raised.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
323 \item[(2)] A left shift by \var{n} bits is equivalent to
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
324 multiplication by \code{pow(2, \var{n})} without overflow check.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
325 \item[(3)] A right shift by \var{n} bits is equivalent to
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
326 division by \code{pow(2, \var{n})} without overflow check.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
327 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
328
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
329
17658
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
330 \subsection{Iterator Types \label{typeiter}}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
331
17663
d76649bd38d0 The general iteration support is part of 2.2, not 2.1 -- fixed the version
Fred Drake <fdrake@acm.org>
parents: 17658
diff changeset
332 \versionadded{2.2}
17658
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
333 \index{iterator protocol}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
334 \index{protocol!iterator}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
335 \index{sequence!iteration}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
336 \index{container!iteration over}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
337
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
338 Python supports a concept of iteration over containers. This is
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
339 implemented using two distinct methods; these are used to allow
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
340 user-defined classes to support iteration. Sequences, described below
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
341 in more detail, always support the iteration methods.
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
342
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
343 One method needs to be defined for container objects to provide
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
344 iteration support:
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
345
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
346 \begin{methoddesc}[container]{__iter__}{}
18839
ab8aa4302109 Typo fix.
Greg Ward <gward@python.net>
parents: 18829
diff changeset
347 Return an iterator object. The object is required to support the
17658
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
348 iterator protocol described below. If a container supports
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
349 different types of iteration, additional methods can be provided to
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
350 specifically request iterators for those iteration types. (An
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
351 example of an object supporting multiple forms of iteration would be
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
352 a tree structure which supports both breadth-first and depth-first
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
353 traversal.) This method corresponds to the \member{tp_iter} slot of
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
354 the type structure for Python objects in the Python/C API.
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
355 \end{methoddesc}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
356
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
357 The iterator objects themselves are required to support the following
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
358 two methods, which together form the \dfn{iterator protocol}:
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
359
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
360 \begin{methoddesc}[iterator]{__iter__}{}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
361 Return the iterator object itself. This is required to allow both
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
362 containers and iterators to be used with the \keyword{for} and
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
363 \keyword{in} statements. This method corresponds to the
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
364 \member{tp_iter} slot of the type structure for Python objects in
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
365 the Python/C API.
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
366 \end{methoddesc}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
367
17663
d76649bd38d0 The general iteration support is part of 2.2, not 2.1 -- fixed the version
Fred Drake <fdrake@acm.org>
parents: 17658
diff changeset
368 \begin{methoddesc}[iterator]{next}{}
17658
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
369 Return the next item from the container. If there are no further
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
370 items, raise the \exception{StopIteration} exception. This method
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
371 corresponds to the \member{tp_iternext} slot of the type structure
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
372 for Python objects in the Python/C API.
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
373 \end{methoddesc}
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
374
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
375 Python defines several iterator objects to support iteration over
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
376 general and specific sequence types, dictionaries, and other more
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
377 specialized forms. The specific types are not important beyond their
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
378 implementation of the iterator protocol.
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
379
24253
62f4b45b05fd Record the decision that StopIteration is a sink state (see recent
Guido van Rossum <guido@python.org>
parents: 24227
diff changeset
380 The intention of the protocol is that once an iterator's
62f4b45b05fd Record the decision that StopIteration is a sink state (see recent
Guido van Rossum <guido@python.org>
parents: 24227
diff changeset
381 \method{next()} method raises \exception{StopIteration}, it will
62f4b45b05fd Record the decision that StopIteration is a sink state (see recent
Guido van Rossum <guido@python.org>
parents: 24227
diff changeset
382 continue to do so on subsequent calls. Implementations that
62f4b45b05fd Record the decision that StopIteration is a sink state (see recent
Guido van Rossum <guido@python.org>
parents: 24227
diff changeset
383 do not obey this property are deemed broken. (This constraint
62f4b45b05fd Record the decision that StopIteration is a sink state (see recent
Guido van Rossum <guido@python.org>
parents: 24227
diff changeset
384 was added in Python 2.3; in Python 2.2, various iterators are
62f4b45b05fd Record the decision that StopIteration is a sink state (see recent
Guido van Rossum <guido@python.org>
parents: 24227
diff changeset
385 broken according to this rule.)
62f4b45b05fd Record the decision that StopIteration is a sink state (see recent
Guido van Rossum <guido@python.org>
parents: 24227
diff changeset
386
17658
d6498b1ef50d Added section describing the iterator protocol.
Fred Drake <fdrake@acm.org>
parents: 17616
diff changeset
387
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
388 \subsection{Sequence Types \label{typesseq}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
389
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
390 There are six sequence types: strings, Unicode strings, lists,
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
391 tuples, buffers, and xrange objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
392
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
393 String literals are written in single or double quotes:
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
394 \code{'xyzzy'}, \code{"frobozz"}. See chapter 2 of the
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
395 \citetitle[../ref/strings.html]{Python Reference Manual} for more about
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
396 string literals. Unicode strings are much like strings, but are
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
397 specified in the syntax using a preceeding \character{u} character:
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
398 \code{u'abc'}, \code{u"def"}. Lists are constructed with square brackets,
11463
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
399 separating items with commas: \code{[a, b, c]}. Tuples are
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
400 constructed by the comma operator (not within square brackets), with
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
401 or without enclosing parentheses, but an empty tuple must have the
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
402 enclosing parentheses, e.g., \code{a, b, c} or \code{()}. A single
18395
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
403 item tuple must have a trailing comma, e.g., \code{(d,)}.
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
404 \obindex{sequence}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
405 \obindex{string}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
406 \obindex{Unicode}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
407 \obindex{tuple}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
408 \obindex{list}
18395
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
409
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
410 Buffer objects are not directly supported by Python syntax, but can be
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
411 created by calling the builtin function
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
412 \function{buffer()}.\bifuncindex{buffer}. They don't support
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
413 concatenation or repetition.
18395
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
414 \obindex{buffer}
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
415
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
416 Xrange objects are similar to buffers in that there is no specific
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
417 syntax to create them, but they are created using the \function{xrange()}
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
418 function.\bifuncindex{xrange} They don't support slicing,
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
419 concatenation or repetition, and using \code{in}, \code{not in},
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
420 \function{min()} or \function{max()} on them is inefficient.
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
421 \obindex{xrange}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
422
18395
1d0d3e6a3201 List constraints on xrange() objects.
Guido van Rossum <guido@python.org>
parents: 18391
diff changeset
423 Most sequence types support the following operations. The \samp{in} and
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
424 \samp{not in} operations have the same priorities as the comparison
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
425 operations. The \samp{+} and \samp{*} operations have the same
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
426 priority as the corresponding numeric operations.\footnote{They must
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
427 have since the parser can't tell the type of the operands.}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
428
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
429 This table lists the sequence operations sorted in ascending priority
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
430 (operations in the same box have the same priority). In the table,
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
431 \var{s} and \var{t} are sequences of the same type; \var{n}, \var{i}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
432 and \var{j} are integers:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
433
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
434 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
435 \lineiii{\var{x} in \var{s}}{\code{1} if an item of \var{s} is equal to \var{x}, else \code{0}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
436 \lineiii{\var{x} not in \var{s}}{\code{0} if an item of \var{s} is
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
437 equal to \var{x}, else \code{1}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
438 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
439 \lineiii{\var{s} + \var{t}}{the concatenation of \var{s} and \var{t}}{}
19529
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
440 \lineiii{\var{s} * \var{n}\textrm{,} \var{n} * \var{s}}{\var{n} shallow copies of \var{s} concatenated}{(1)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
441 \hline
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
442 \lineiii{\var{s}[\var{i}]}{\var{i}'th item of \var{s}, origin 0}{(2)}
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
443 \lineiii{\var{s}[\var{i}:\var{j}]}{slice of \var{s} from \var{i} to \var{j}}{(2), (3)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
444 \hline
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
445 \lineiii{len(\var{s})}{length of \var{s}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
446 \lineiii{min(\var{s})}{smallest item of \var{s}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
447 \lineiii{max(\var{s})}{largest item of \var{s}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
448 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
449 \indexiii{operations on}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
450 \bifuncindex{len}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
451 \bifuncindex{min}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
452 \bifuncindex{max}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
453 \indexii{concatenation}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
454 \indexii{repetition}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
455 \indexii{subscript}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
456 \indexii{slice}{operation}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
457 \opindex{in}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
458 \opindex{not in}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
459
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
460 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
461 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
462
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
463 \begin{description}
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
464 \item[(1)] Values of \var{n} less than \code{0} are treated as
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
465 \code{0} (which yields an empty sequence of the same type as
19529
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
466 \var{s}). Note also that the copies are shallow; nested structures
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
467 are not copied. This often haunts new Python programmers; consider:
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
468
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
469 \begin{verbatim}
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
470 >>> lists = [[]] * 3
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
471 >>> lists
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
472 [[], [], []]
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
473 >>> lists[0].append(3)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
474 >>> lists
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
475 [[3], [3], [3]]
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
476 \end{verbatim}
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
477
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
478 What has happened is that \code{lists} is a list containing three
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
479 copies of the list \code{[[]]} (a one-element list containing an
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
480 empty list), but the contained list is shared by each copy. You can
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
481 create a list of different lists this way:
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
482
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
483 \begin{verbatim}
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
484 >>> lists = [[] for i in range(3)]
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
485 >>> lists[0].append(3)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
486 >>> lists[1].append(5)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
487 >>> lists[2].append(7)
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
488 >>> lists
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
489 [[3], [5], [7]]
dd8d6153a8c6 Added explanation that [...] * n generates shallow copies of [...], so
Fred Drake <fdrake@acm.org>
parents: 19243
diff changeset
490 \end{verbatim}
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
491
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
492 \item[(2)] If \var{i} or \var{j} is negative, the index is relative to
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
493 the end of the string: \code{len(\var{s}) + \var{i}} or
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
494 \code{len(\var{s}) + \var{j}} is substituted. But note that \code{-0} is
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
495 still \code{0}.
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
496
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
497 \item[(3)] The slice of \var{s} from \var{i} to \var{j} is defined as
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
498 the sequence of items with index \var{k} such that \code{\var{i} <=
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
499 \var{k} < \var{j}}. If \var{i} or \var{j} is greater than
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
500 \code{len(\var{s})}, use \code{len(\var{s})}. If \var{i} is omitted,
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
501 use \code{0}. If \var{j} is omitted, use \code{len(\var{s})}. If
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
502 \var{i} is greater than or equal to \var{j}, the slice is empty.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
503 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
504
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
505
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
506 \subsubsection{String Methods \label{string-methods}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
507
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
508 These are the string methods which both 8-bit strings and Unicode
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
509 objects support:
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
510
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
511 \begin{methoddesc}[string]{capitalize}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
512 Return a copy of the string with only its first character capitalized.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
513 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
514
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
515 \begin{methoddesc}[string]{center}{width}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
516 Return centered in a string of length \var{width}. Padding is done
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
517 using spaces.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
518 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
519
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
520 \begin{methoddesc}[string]{count}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
521 Return the number of occurrences of substring \var{sub} in string
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
522 S\code{[\var{start}:\var{end}]}. Optional arguments \var{start} and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
523 \var{end} are interpreted as in slice notation.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
524 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
525
21332
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
526 \begin{methoddesc}[string]{decode}{\optional{encoding\optional{, errors}}}
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
527 Decodes the string using the codec registered for \var{encoding}.
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
528 \var{encoding} defaults to the default string encoding. \var{errors}
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
529 may be given to set a different error handling scheme. The default is
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
530 \code{'strict'}, meaning that encoding errors raise
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
531 \exception{ValueError}. Other possible values are \code{'ignore'} and
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
532 \code{replace'}.
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
533 \versionadded{2.2}
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
534 \end{methoddesc}
fbbd8a4ca7a6 Added documentation for str.decode().
Fred Drake <fdrake@acm.org>
parents: 21177
diff changeset
535
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
536 \begin{methoddesc}[string]{encode}{\optional{encoding\optional{,errors}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
537 Return an encoded version of the string. Default encoding is the current
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
538 default string encoding. \var{errors} may be given to set a different
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
539 error handling scheme. The default for \var{errors} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
540 \code{'strict'}, meaning that encoding errors raise a
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
541 \exception{ValueError}. Other possible values are \code{'ignore'} and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
542 \code{'replace'}.
15332
12aec3381c94 Marc-Andre Lemburg <mal@lemburg.com> noted that the encode() string method
Fred Drake <fdrake@acm.org>
parents: 15005
diff changeset
543 \versionadded{2.0}
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
544 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
545
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
546 \begin{methoddesc}[string]{endswith}{suffix\optional{, start\optional{, end}}}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
547 Return true if the string ends with the specified \var{suffix},
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
548 otherwise return false. With optional \var{start}, test beginning at
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
549 that position. With optional \var{end}, stop comparing at that position.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
550 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
551
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
552 \begin{methoddesc}[string]{expandtabs}{\optional{tabsize}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
553 Return a copy of the string where all tab characters are expanded
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
554 using spaces. If \var{tabsize} is not given, a tab size of \code{8}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
555 characters is assumed.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
556 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
557
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
558 \begin{methoddesc}[string]{find}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
559 Return the lowest index in the string where substring \var{sub} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
560 found, such that \var{sub} is contained in the range [\var{start},
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
561 \var{end}). Optional arguments \var{start} and \var{end} are
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
562 interpreted as in slice notation. Return \code{-1} if \var{sub} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
563 not found.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
564 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
565
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
566 \begin{methoddesc}[string]{index}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
567 Like \method{find()}, but raise \exception{ValueError} when the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
568 substring is not found.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
569 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
570
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
571 \begin{methoddesc}[string]{isalnum}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
572 Return true if all characters in the string are alphanumeric and there
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
573 is at least one character, false otherwise.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
574 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
575
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
576 \begin{methoddesc}[string]{isalpha}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
577 Return true if all characters in the string are alphabetic and there
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
578 is at least one character, false otherwise.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
579 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
580
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
581 \begin{methoddesc}[string]{isdigit}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
582 Return true if there are only digit characters, false otherwise.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
583 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
584
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
585 \begin{methoddesc}[string]{islower}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
586 Return true if all cased characters in the string are lowercase and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
587 there is at least one cased character, false otherwise.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
588 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
589
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
590 \begin{methoddesc}[string]{isspace}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
591 Return true if there are only whitespace characters in the string and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
592 the string is not empty, false otherwise.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
593 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
594
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
595 \begin{methoddesc}[string]{istitle}{}
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
596 Return true if the string is a titlecased string: uppercase
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
597 characters may only follow uncased characters and lowercase characters
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
598 only cased ones. Return false otherwise.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
599 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
600
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
601 \begin{methoddesc}[string]{isupper}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
602 Return true if all cased characters in the string are uppercase and
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
603 there is at least one cased character, false otherwise.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
604 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
605
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
606 \begin{methoddesc}[string]{join}{seq}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
607 Return a string which is the concatenation of the strings in the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
608 sequence \var{seq}. The separator between elements is the string
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
609 providing this method.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
610 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
611
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
612 \begin{methoddesc}[string]{ljust}{width}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
613 Return the string left justified in a string of length \var{width}.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
614 Padding is done using spaces. The original string is returned if
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
615 \var{width} is less than \code{len(\var{s})}.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
616 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
617
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
618 \begin{methoddesc}[string]{lower}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
619 Return a copy of the string converted to lowercase.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
620 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
621
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
622 \begin{methoddesc}[string]{lstrip}{\optional{chars}}
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
623 Return a copy of the string with leading characters removed. If
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
624 \var{chars} is omitted or \code{None}, whitespace characters are
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
625 removed. If given and not \code{None}, \var{chars} must be a string;
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
626 the characters in the string will be stripped from the beginning of
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
627 the string this method is called on.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
628 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
629
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
630 \begin{methoddesc}[string]{replace}{old, new\optional{, maxsplit}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
631 Return a copy of the string with all occurrences of substring
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
632 \var{old} replaced by \var{new}. If the optional argument
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
633 \var{maxsplit} is given, only the first \var{maxsplit} occurrences are
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
634 replaced.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
635 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
636
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
637 \begin{methoddesc}[string]{rfind}{sub \optional{,start \optional{,end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
638 Return the highest index in the string where substring \var{sub} is
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
639 found, such that \var{sub} is contained within s[start,end]. Optional
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
640 arguments \var{start} and \var{end} are interpreted as in slice
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
641 notation. Return \code{-1} on failure.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
642 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
643
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
644 \begin{methoddesc}[string]{rindex}{sub\optional{, start\optional{, end}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
645 Like \method{rfind()} but raises \exception{ValueError} when the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
646 substring \var{sub} is not found.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
647 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
648
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
649 \begin{methoddesc}[string]{rjust}{width}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
650 Return the string right justified in a string of length \var{width}.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
651 Padding is done using spaces. The original string is returned if
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
652 \var{width} is less than \code{len(\var{s})}.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
653 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
654
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
655 \begin{methoddesc}[string]{rstrip}{\optional{chars}}
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
656 Return a copy of the string with trailing characters removed. If
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
657 \var{chars} is omitted or \code{None}, whitespace characters are
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
658 removed. If given and not \code{None}, \var{chars} must be a string;
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
659 the characters in the string will be stripped from the end of the
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
660 string this method is called on.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
661 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
662
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
663 \begin{methoddesc}[string]{split}{\optional{sep \optional{,maxsplit}}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
664 Return a list of the words in the string, using \var{sep} as the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
665 delimiter string. If \var{maxsplit} is given, at most \var{maxsplit}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
666 splits are done. If \var{sep} is not specified or \code{None}, any
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
667 whitespace string is a separator.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
668 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
669
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
670 \begin{methoddesc}[string]{splitlines}{\optional{keepends}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
671 Return a list of the lines in the string, breaking at line
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
672 boundaries. Line breaks are not included in the resulting list unless
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
673 \var{keepends} is given and true.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
674 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
675
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
676 \begin{methoddesc}[string]{startswith}{prefix\optional{,
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
677 start\optional{, end}}}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
678 Return true if string starts with the \var{prefix}, otherwise
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
679 return false. With optional \var{start}, test string beginning at
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
680 that position. With optional \var{end}, stop comparing string at that
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
681 position.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
682 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
683
23017
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
684 \begin{methoddesc}[string]{strip}{\optional{chars}}
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
685 Return a copy of the string with leading and trailing characters
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
686 removed. If \var{chars} is omitted or \code{None}, whitespace
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
687 characters are removed. If given and not \code{None}, \var{chars}
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
688 must be a string; the characters in the string will be stripped from
44637bd7f59b Document the optional argument to the .strip(), .rstrip(), .strip() string
Fred Drake <fdrake@acm.org>
parents: 22994
diff changeset
689 the both ends of the string this method is called on.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
690 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
691
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
692 \begin{methoddesc}[string]{swapcase}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
693 Return a copy of the string with uppercase characters converted to
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
694 lowercase and vice versa.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
695 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
696
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
697 \begin{methoddesc}[string]{title}{}
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
698 Return a titlecased version of the string: words start with uppercase
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
699 characters, all remaining cased characters are lowercase.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
700 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
701
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
702 \begin{methoddesc}[string]{translate}{table\optional{, deletechars}}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
703 Return a copy of the string where all characters occurring in the
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
704 optional argument \var{deletechars} are removed, and the remaining
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
705 characters have been mapped through the given translation table, which
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
706 must be a string of length 256.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
707 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
708
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
709 \begin{methoddesc}[string]{upper}{}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
710 Return a copy of the string converted to uppercase.
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
711 \end{methoddesc}
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
712
23045
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
713 \begin{methoddesc}[string]{zfill}{width}
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
714 Return the numeric string left filled with zeros in a string
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
715 of length \var{width}. The original string is returned if
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
716 \var{width} is less than \code{len(\var{s})}.
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
717 \end{methoddesc}
8b1268bc371a Apply the second version of SF patch http://www.python.org/sf/536241
Walter Dörwald <walter@livinglogic.de>
parents: 23017
diff changeset
718
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
719
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
720 \subsubsection{String Formatting Operations \label{typesseq-strings}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
721
21177
7d1eac41ce3e Slightly improved indexing for the string-% operator, thanks to comments
Fred Drake <fdrake@acm.org>
parents: 21163
diff changeset
722 \index{formatting, string (\%{})}
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
723 \index{interpolation, string (\%{})}
14552
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
724 \index{string!formatting}
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
725 \index{string!interpolation}
14552
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
726 \index{printf-style formatting}
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
727 \index{sprintf-style formatting}
21177
7d1eac41ce3e Slightly improved indexing for the string-% operator, thanks to comments
Fred Drake <fdrake@acm.org>
parents: 21163
diff changeset
728 \index{\protect\%{} formatting}
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
729 \index{\protect\%{} interpolation}
14552
a8d1c030b19f Add some index entries to make it easier to find information on
Fred Drake <fdrake@acm.org>
parents: 14520
diff changeset
730
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
731 String and Unicode objects have one unique built-in operation: the
21542
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
732 \code{\%} operator (modulo). This is also known as the string
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
733 \emph{formatting} or \emph{interpolation} operator. Given
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
734 \code{\var{format} \% \var{values}} (where \var{format} is a string or
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
735 Unicode object), \code{\%} conversion specifications in \var{format}
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
736 are replaced with zero or more elements of \var{values}. The effect
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
737 is similar to the using \cfunction{sprintf()} in the C language. If
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
738 \var{format} is a Unicode object, or if any of the objects being
5d4135609efc Added index entries similar to some recommended by Skip, and used the word
Fred Drake <fdrake@acm.org>
parents: 21332
diff changeset
739 converted using the \code{\%s} conversion are Unicode objects, the
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
740 result will also be a Unicode object.
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
741
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
742 If \var{format} requires a single argument, \var{values} may be a
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
743 single non-tuple object. \footnote{To format only a tuple you
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
744 should therefore provide a singleton tuple whose only element
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
745 is the tuple to be formatted.} Otherwise, \var{values} must be a tuple with
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
746 exactly the number of items specified by the format string, or a
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
747 single mapping object (for example, a dictionary).
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
748
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
749 A conversion specifier contains two or more characters and has the
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
750 following components, which must occur in this order:
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
751
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
752 \begin{enumerate}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
753 \item The \character{\%} character, which marks the start of the
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
754 specifier.
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
755 \item Mapping key (optional), consisting of a parenthesised sequence
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
756 of characters (for example, \code{(somename)}).
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
757 \item Conversion flags (optional), which affect the result of some
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
758 conversion types.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
759 \item Minimum field width (optional). If specified as an
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
760 \character{*} (asterisk), the actual width is read from the
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
761 next element of the tuple in \var{values}, and the object to
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
762 convert comes after the minimum field width and optional
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
763 precision.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
764 \item Precision (optional), given as a \character{.} (dot) followed
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
765 by the precision. If specified as \character{*} (an
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
766 asterisk), the actual width is read from the next element of
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
767 the tuple in \var{values}, and the value to convert comes after
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
768 the precision.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
769 \item Length modifier (optional).
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
770 \item Conversion type.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
771 \end{enumerate}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
772
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
773 When the right argument is a dictionary (or other mapping type), then
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
774 the formats in the string \emph{must} include a parenthesised mapping key into
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
775 that dictionary inserted immediately after the \character{\%}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
776 character. The mapping key selects the value to be formatted from the
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
777 mapping. For example:
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
778
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
779 \begin{verbatim}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
780 >>> print '%(language)s has %(#)03d quote types.' % \
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
781 {'language': "Python", "#": 2}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
782 Python has 002 quote types.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
783 \end{verbatim}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
784
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
785 In this case no \code{*} specifiers may occur in a format (since they
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
786 require a sequential parameter list).
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
787
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
788 The conversion flag characters are:
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
789
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
790 \begin{tableii}{c|l}{character}{Flag}{Meaning}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
791 \lineii{\#}{The value conversion will use the ``alternate form''
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
792 (where defined below).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
793 \lineii{0}{The conversion will be zero padded.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
794 \lineii{-}{The converted value is left adjusted (overrides
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
795 \character{-}).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
796 \lineii{{~}}{(a space) A blank should be left before a positive number
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
797 (or empty string) produced by a signed conversion.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
798 \lineii{+}{A sign character (\character{+} or \character{-}) will
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
799 precede the conversion (overrides a "space" flag).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
800 \end{tableii}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
801
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
802 The length modifier may be \code{h}, \code{l}, and \code{L} may be
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
803 present, but are ignored as they are not necessary for Python.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
804
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
805 The conversion types are:
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
806
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
807 \begin{tableii}{c|l}{character}{Conversion}{Meaning}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
808 \lineii{d}{Signed integer decimal.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
809 \lineii{i}{Signed integer decimal.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
810 \lineii{o}{Unsigned octal.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
811 \lineii{u}{Unsigned decimal.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
812 \lineii{x}{Unsigned hexidecimal (lowercase).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
813 \lineii{X}{Unsigned hexidecimal (uppercase).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
814 \lineii{e}{Floating point exponential format (lowercase).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
815 \lineii{E}{Floating point exponential format (uppercase).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
816 \lineii{f}{Floating point decimal format.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
817 \lineii{F}{Floating point decimal format.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
818 \lineii{g}{Same as \character{e} if exponent is greater than -4 or
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
819 less than precision, \character{f} otherwise.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
820 \lineii{G}{Same as \character{E} if exponent is greater than -4 or
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
821 less than precision, \character{F} otherwise.}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
822 \lineii{c}{Single character (accepts integer or single character
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
823 string).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
824 \lineii{r}{String (converts any python object using
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
825 \function{repr()}).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
826 \lineii{s}{String (converts any python object using
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
827 \function{str()}).}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
828 \lineii{\%}{No argument is converted, results in a \character{\%}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
829 character in the result. (The complete specification is
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
830 \code{\%\%}.)}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
831 \end{tableii}
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
832
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
833 % XXX Examples?
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
834
23320
23bf68778a2a Add a note about when the "%r" formatting code was added.
Fred Drake <fdrake@acm.org>
parents: 23045
diff changeset
835 (The \code{\%r} conversion was added in Python 2.0.)
16285
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
836
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
837 Since Python strings have an explicit length, \code{\%s} conversions
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
838 do not assume that \code{'\e0'} is the end of the string.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
839
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
840 For safety reasons, floating point precisions are clipped to 50;
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
841 \code{\%f} conversions for numbers whose absolute value is over 1e25
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
842 are replaced by \code{\%g} conversions.\footnote{
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
843 These numbers are fairly arbitrary. They are intended to
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
844 avoid printing endless strings of meaningless digits without hampering
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
845 correct use and without having to know the exact precision of floating
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
846 point values on a particular machine.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
847 } All other errors raise exceptions.
15e0c10092bb Massively improved documentation for string formatting operations,
Fred Drake <fdrake@acm.org>
parents: 15926
diff changeset
848
21163
7b6879714b74 Make no assumption about how modules are built when referring to them; this
Fred Drake <fdrake@acm.org>
parents: 21159
diff changeset
849 Additional string operations are defined in standard modules
7b6879714b74 Make no assumption about how modules are built when referring to them; this
Fred Drake <fdrake@acm.org>
parents: 21159
diff changeset
850 \refmodule{string}\refstmodindex{string} and
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
851 \refmodule{re}.\refstmodindex{re}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
852
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
853
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
854 \subsubsection{XRange Type \label{typesseq-xrange}}
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
855
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
856 The xrange\obindex{xrange} type is an immutable sequence which is
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
857 commonly used for looping. The advantage of the xrange type is that an
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
858 xrange object will always take the same amount of memory, no matter the
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
859 size of the range it represents. There are no consistent performance
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
860 advantages.
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
861
18391
aadd99830531 Rip out the fancy behaviors of xrange that nobody uses: repeat, slice,
Guido van Rossum <guido@python.org>
parents: 18286
diff changeset
862 XRange objects have very little behavior: they only support indexing
aadd99830531 Rip out the fancy behaviors of xrange that nobody uses: repeat, slice,
Guido van Rossum <guido@python.org>
parents: 18286
diff changeset
863 and the \function{len()} function.
13967
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
864
7b7ee58901fb Document the range type, as suggested by Denis S. Otkidach
Fred Drake <fdrake@acm.org>
parents: 13933
diff changeset
865
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
866 \subsubsection{Mutable Sequence Types \label{typesseq-mutable}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
867
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
868 List objects support additional operations that allow in-place
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
869 modification of the object.
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
870 Other mutable sequence types (when added to the language) should
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
871 also support these operations.
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
872 Strings and tuples are immutable sequence types: such objects cannot
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
873 be modified once created.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
874 The following operations are defined on mutable sequence types (where
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
875 \var{x} is an arbitrary object):
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
876 \indexiii{mutable}{sequence}{types}
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
877 \obindex{list}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
878
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
879 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
880 \lineiii{\var{s}[\var{i}] = \var{x}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
881 {item \var{i} of \var{s} is replaced by \var{x}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
882 \lineiii{\var{s}[\var{i}:\var{j}] = \var{t}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
883 {slice of \var{s} from \var{i} to \var{j} is replaced by \var{t}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
884 \lineiii{del \var{s}[\var{i}:\var{j}]}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
885 {same as \code{\var{s}[\var{i}:\var{j}] = []}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
886 \lineiii{\var{s}.append(\var{x})}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
887 {same as \code{\var{s}[len(\var{s}):len(\var{s})] = [\var{x}]}}{(1)}
9318
8a26e55e18b8 Document the new list.extend() method. Interesting enough, the
Barry Warsaw <barry@python.org>
parents: 9083
diff changeset
888 \lineiii{\var{s}.extend(\var{x})}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
889 {same as \code{\var{s}[len(\var{s}):len(\var{s})] = \var{x}}}{(2)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
890 \lineiii{\var{s}.count(\var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
891 {return number of \var{i}'s for which \code{\var{s}[\var{i}] == \var{x}}}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
892 \lineiii{\var{s}.index(\var{x})}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
893 {return smallest \var{i} such that \code{\var{s}[\var{i}] == \var{x}}}{(3)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
894 \lineiii{\var{s}.insert(\var{i}, \var{x})}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
895 {same as \code{\var{s}[\var{i}:\var{i}] = [\var{x}]}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
896 if \code{\var{i} >= 0}}{(4)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
897 \lineiii{\var{s}.pop(\optional{\var{i}})}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
898 {same as \code{\var{x} = \var{s}[\var{i}]; del \var{s}[\var{i}]; return \var{x}}}{(5)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
899 \lineiii{\var{s}.remove(\var{x})}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
900 {same as \code{del \var{s}[\var{s}.index(\var{x})]}}{(3)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
901 \lineiii{\var{s}.reverse()}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
902 {reverses the items of \var{s} in place}{(6)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
903 \lineiii{\var{s}.sort(\optional{\var{cmpfunc}})}
24459
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
904 {sort the items of \var{s} in place}{(6), (7), (8)}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
905 \end{tableiii}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
906 \indexiv{operations on}{mutable}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
907 \indexiii{operations on}{sequence}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
908 \indexiii{operations on}{list}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
909 \indexii{subscript}{assignment}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
910 \indexii{slice}{assignment}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
911 \stindex{del}
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
912 \withsubitem{(list method)}{
11183
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
913 \ttindex{append()}\ttindex{extend()}\ttindex{count()}\ttindex{index()}
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
914 \ttindex{insert()}\ttindex{pop()}\ttindex{remove()}\ttindex{reverse()}
9523
ed6cacddc6c6 Fix indexing of func_code attribute; this is on a function, not a code
Fred Drake <fdrake@acm.org>
parents: 9461
diff changeset
915 \ttindex{sort()}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
916 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
917 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
918 \begin{description}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
919 \item[(1)] The C implementation of Python historically accepted
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
920 multiple parameters and implicitly joined them into a tuple;
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
921 Use of this misfeature has been deprecated since Python 1.4,
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
922 and became an error with the introduction of Python 2.0.
23778
245224d1b8c9 This is my nearly two year old patch
Michael W. Hudson <mwh@python.net>
parents: 23515
diff changeset
923
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
924 \item[(2)] Raises an exception when \var{x} is not a list object. The
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
925 \method{extend()} method is experimental and not supported by
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
926 mutable sequence types other than lists.
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
927
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
928 \item[(3)] Raises \exception{ValueError} when \var{x} is not found in
11183
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
929 \var{s}.
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
930
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
931 \item[(4)] When a negative index is passed as the first parameter to
20701
5f6850d1f9e8 Explain what [].insert() does when the target index is negative.
Fred Drake <fdrake@acm.org>
parents: 20580
diff changeset
932 the \method{insert()} method, the new element is prepended to the
5f6850d1f9e8 Explain what [].insert() does when the target index is negative.
Fred Drake <fdrake@acm.org>
parents: 20580
diff changeset
933 sequence.
5f6850d1f9e8 Explain what [].insert() does when the target index is negative.
Fred Drake <fdrake@acm.org>
parents: 20580
diff changeset
934
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
935 \item[(5)] The \method{pop()} method is only supported by the list and
13777
b3903e05017f Stop lying about [].pop() being experimental! There is no backing it out
Fred Drake <fdrake@acm.org>
parents: 13772
diff changeset
936 array types. The optional argument \var{i} defaults to \code{-1},
b3903e05017f Stop lying about [].pop() being experimental! There is no backing it out
Fred Drake <fdrake@acm.org>
parents: 13772
diff changeset
937 so that by default the last item is removed and returned.
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
938
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
939 \item[(6)] The \method{sort()} and \method{reverse()} methods modify the
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
940 list in place for economy of space when sorting or reversing a large
18829
1bc1fdf1482b trivial rewording in footnote 5.
Skip Montanaro <skip@pobox.com>
parents: 18416
diff changeset
941 list. To remind you that they operate by side effect, they don't return
1bc1fdf1482b trivial rewording in footnote 5.
Skip Montanaro <skip@pobox.com>
parents: 18416
diff changeset
942 the sorted or reversed list.
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
943
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
944 \item[(7)] The \method{sort()} method takes an optional argument
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
945 specifying a comparison function of two arguments (list items) which
20173
f100793ca9af The list.sort() docs require a function that returns -1, 0 or +1. That's
Tim Peters <tim.peters@gmail.com>
parents: 20045
diff changeset
946 should return a negative, zero or positive number depending on whether
11183
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
947 the first argument is considered smaller than, equal to, or larger
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
948 than the second argument. Note that this slows the sorting process
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
949 down considerably; e.g. to sort a list in reverse order it is much
24459
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
950 faster to call method \method{sort()} followed by
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
951 \method{reverse()} than to use method
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
952 \method{sort()} with a comparison function that reverses the
11183
1e0b1967be7f In note mentioning [].remove()'s exception, tell what exception is
Fred Drake <fdrake@acm.org>
parents: 11100
diff changeset
953 ordering of the elements.
24459
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
954
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
955 \item[(8)] Whether the \method{sort()} method is stable is not defined by
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
956 the language (a sort is stable if it guarantees not to change the
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
957 relative order of elements that compare equal). In the C
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
958 implementation of Python, sorts were stable only by accident through
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
959 Python 2.2. The C implementation of Python 2.3 introduced a stable
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
960 \method{sort()} method, but code that intends to be portable across
189eb6fa9ded Added new footnote about list.sort() stability. Repaired footnote about
Tim Peters <tim.peters@gmail.com>
parents: 24253
diff changeset
961 implementations and versions must not rely on stability.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
962 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
963
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
964
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
965 \subsection{Mapping Types \label{typesmapping}}
15005
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
966 \obindex{mapping}
0cf5111bf09c Use \obindex{...} instead of \indexii{...}{type} in many places; this is
Fred Drake <fdrake@acm.org>
parents: 14710
diff changeset
967 \obindex{dictionary}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
968
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
969 A \dfn{mapping} object maps immutable values to
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
970 arbitrary objects. Mappings are mutable objects. There is currently
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
971 only one standard mapping type, the \dfn{dictionary}. A dictionary's keys are
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
972 almost arbitrary values. Only values containing lists, dictionaries
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
973 or other mutable types (that are compared by value rather than by
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
974 object identity) may not be used as keys.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
975 Numeric types used for keys obey the normal rules for numeric
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
976 comparison: if two numbers compare equal (e.g. \code{1} and
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
977 \code{1.0}) then they can be used interchangeably to index the same
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
978 dictionary entry.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
979
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
980 Dictionaries are created by placing a comma-separated list of
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
981 \code{\var{key}: \var{value}} pairs within braces, for example:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
982 \code{\{'jack': 4098, 'sjoerd': 4127\}} or
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
983 \code{\{4098: 'jack', 4127: 'sjoerd'\}}.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
984
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
985 The following operations are defined on mappings (where \var{a} and
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
986 \var{b} are mappings, \var{k} is a key, and \var{v} and \var{x} are
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
987 arbitrary objects):
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
988 \indexiii{operations on}{mapping}{types}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
989 \indexiii{operations on}{dictionary}{type}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
990 \stindex{del}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
991 \bifuncindex{len}
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
992 \withsubitem{(dictionary method)}{
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
993 \ttindex{clear()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
994 \ttindex{copy()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
995 \ttindex{has_key()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
996 \ttindex{items()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
997 \ttindex{keys()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
998 \ttindex{update()}
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
999 \ttindex{values()}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1000 \ttindex{get()}}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1001
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1002 \begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1003 \lineiii{len(\var{a})}{the number of items in \var{a}}{}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1004 \lineiii{\var{a}[\var{k}]}{the item of \var{a} with key \var{k}}{(1)}
13764
fdbc8730d356 Two minor nits from Gerry Weiner (no working email address) about
Fred Drake <fdrake@acm.org>
parents: 13222
diff changeset
1005 \lineiii{\var{a}[\var{k}] = \var{v}}
fdbc8730d356 Two minor nits from Gerry Weiner (no working email address) about
Fred Drake <fdrake@acm.org>
parents: 13222
diff changeset
1006 {set \code{\var{a}[\var{k}]} to \var{v}}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1007 {}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1008 \lineiii{del \var{a}[\var{k}]}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1009 {remove \code{\var{a}[\var{k}]} from \var{a}}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1010 {(1)}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1011 \lineiii{\var{a}.clear()}{remove all items from \code{a}}{}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1012 \lineiii{\var{a}.copy()}{a (shallow) copy of \code{a}}{}
17616
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1013 \lineiii{\var{a}.has_key(\var{k})}
17594
bf94af396b1e Implement, test and document "key in dict" and "key not in dict".
Guido van Rossum <guido@python.org>
parents: 16778
diff changeset
1014 {\code{1} if \var{a} has a key \var{k}, else \code{0}}
bf94af396b1e Implement, test and document "key in dict" and "key not in dict".
Guido van Rossum <guido@python.org>
parents: 16778
diff changeset
1015 {}
17616
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1016 \lineiii{\var{k} \code{in} \var{a}}
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1017 {Equivalent to \var{a}.has_key(\var{k})}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1018 {(2)}
17594
bf94af396b1e Implement, test and document "key in dict" and "key not in dict".
Guido van Rossum <guido@python.org>
parents: 16778
diff changeset
1019 \lineiii{\var{k} not in \var{a}}
17616
7acba78e1e09 At the suggestion of Peter Funk, document 'key in dict' and 'key not
Guido van Rossum <guido@python.org>
parents: 17612
diff changeset
1020 {Equivalent to \code{not} \var{a}.has_key(\var{k})}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1021 {(2)}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1022 \lineiii{\var{a}.items()}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1023 {a copy of \var{a}'s list of (\var{key}, \var{value}) pairs}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1024 {(3)}
18085
7e459fb3c332 Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
parents: 17966
diff changeset
1025 \lineiii{\var{a}.keys()}{a copy of \var{a}'s list of keys}{(3)}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1026 \lineiii{\var{a}.update(\var{b})}
13764
fdbc8730d356 Two minor nits from Gerry Weiner (no working email address) about
Fred Drake <fdrake@acm.org>
parents: 13222
diff changeset
1027 {\code{for k in \var{b}.keys(): \var{a}[k] = \var{b}[k]}}
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1028 {}
18085
7e459fb3c332 Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
parents: 17966
diff changeset
1029 \lineiii{\var{a}.values()}{a copy of \var{a}'s list of values}{(3)}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1030 \lineiii{\var{a}.get(\var{k}\optional{, \var{x}})}
17603
d638e419c304 Fix a number of minor markup errors.
Fred Drake <fdrake@acm.org>
parents: 17594
diff changeset
1031 {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}},
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1032 else \var{x}}
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1033 {(4)}
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1034 \lineiii{\var{a}.setdefault(\var{k}\optional{, \var{x}})}
17603
d638e419c304 Fix a number of minor markup errors.
Fred Drake <fdrake@acm.org>
parents: 17594
diff changeset
1035 {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}},
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1036 else \var{x} (also setting it)}
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1037 {(5)}
22994
196dfa7ed348 Add Raymond Hettinger's d.pop(). See SF patch 539949.
Guido van Rossum <guido@python.org>
parents: 22920
diff changeset
1038 \lineiii{\var{a}.pop(\var{k})}
196dfa7ed348 Add Raymond Hettinger's d.pop(). See SF patch 539949.
Guido van Rossum <guido@python.org>
parents: 22920
diff changeset
1039 {remove specified \var{key} and return corresponding \var{value}}
196dfa7ed348 Add Raymond Hettinger's d.pop(). See SF patch 539949.
Guido van Rossum <guido@python.org>
parents: 22920
diff changeset
1040 {}
15522
aaa54752e4ba "Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents: 15463
diff changeset
1041 \lineiii{\var{a}.popitem()}
aaa54752e4ba "Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents: 15463
diff changeset
1042 {remove and return an arbitrary (\var{key}, \var{value}) pair}
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1043 {(6)}
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1044 \lineiii{\var{a}.iteritems()}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1045 {return an iterator over (\var{key}, \var{value}) pairs}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1046 {(2)}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1047 \lineiii{\var{a}.iterkeys()}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1048 {return an iterator over the mapping's keys}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1049 {(2)}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1050 \lineiii{\var{a}.itervalues()}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1051 {return an iterator over the mapping's values}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1052 {(2)}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1053 \end{tableiii}
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1054
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1055 \noindent
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1056 Notes:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1057 \begin{description}
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1058 \item[(1)] Raises a \exception{KeyError} exception if \var{k} is not
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1059 in the map.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1060
17966
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1061 \item[(2)] \versionadded{2.2}
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1062
178bedf9536d Add descriptions of {}.iteritems(), {}.iterkeys(), and {}.itervalues()
Fred Drake <fdrake@acm.org>
parents: 17663
diff changeset
1063 \item[(3)] Keys and values are listed in random order. If
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1064 \method{keys()} and \method{values()} are called with no intervening
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1065 modifications to the dictionary, the two lists will directly
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1066 correspond. This allows the creation of \code{(\var{value},
18085
7e459fb3c332 Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
parents: 17966
diff changeset
1067 \var{key})} pairs using \function{zip()}: \samp{pairs =
7e459fb3c332 Fixed reference to table notes for {}.keys() and {}.items() -- these
Fred Drake <fdrake@acm.org>
parents: 17966
diff changeset
1068 zip(\var{a}.values(), \var{a}.keys())}.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1069
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1070 \item[(4)] Never raises an exception if \var{k} is not in the map,
12223
e82e82b3b9ad Merged changes from the 1.5.2p2 release.
Fred Drake <fdrake@acm.org>
parents: 11463
diff changeset
1071 instead it returns \var{x}. \var{x} is optional; when \var{x} is not
10968
5ba2e4ce58cb Some clarifications on operations for mapping types, based on comments
Fred Drake <fdrake@acm.org>
parents: 10785
diff changeset
1072 provided and \var{k} is not in the map, \code{None} is returned.
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1073
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1074 \item[(5)] \function{setdefault()} is like \function{get()}, except
13894
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1075 that if \var{k} is missing, \var{x} is both returned and inserted into
77b9e041b595 Barry's patch to document the new setdefault() method. Slightly
Guido van Rossum <guido@python.org>
parents: 13780
diff changeset
1076 the dictionary as the value of \var{k}.
15522
aaa54752e4ba "Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents: 15463
diff changeset
1077
18286
bc05a95242a3 Remove the restriction on a mapping's .update() method.
Barry Warsaw <barry@python.org>
parents: 18085
diff changeset
1078 \item[(6)] \function{popitem()} is useful to destructively iterate
15522
aaa54752e4ba "Documentation" for {}.popitem().
Guido van Rossum <guido@python.org>
parents: 15463
diff changeset
1079 over a dictionary, as often used in set algorithms.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1080 \end{description}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1081
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1082
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1083 \subsection{File Objects
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1084 \label{bltin-file-objects}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1085
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1086 File objects\obindex{file} are implemented using C's \code{stdio}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1087 package and can be created with the built-in constructor
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1088 \function{file()}\bifuncindex{file} described in section
20764
37b8d92e12f5 Mention the new file() builtin in the section on file objects.
Tim Peters <tim.peters@gmail.com>
parents: 20701
diff changeset
1089 \ref{built-in-funcs}, ``Built-in Functions.''\footnote{\function{file()}
37b8d92e12f5 Mention the new file() builtin in the section on file objects.
Tim Peters <tim.peters@gmail.com>
parents: 20701
diff changeset
1090 is new in Python 2.2. The older built-in \function{open()} is an
37b8d92e12f5 Mention the new file() builtin in the section on file objects.
Tim Peters <tim.peters@gmail.com>
parents: 20701
diff changeset
1091 alias for \function{file()}.}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1092 File objects are also returned
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1093 by some other built-in functions and methods, such as
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
1094 \function{os.popen()} and \function{os.fdopen()} and the
9461
9ffd604807c2 Don't describe something as "below"; that won't make sense for the
Fred Drake <fdrake@acm.org>
parents: 9318
diff changeset
1095 \method{makefile()} method of socket objects.
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
1096 \refstmodindex{os}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1097 \refbimodindex{socket}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1098
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1099 When a file operation fails for an I/O-related reason, the exception
9558
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
1100 \exception{IOError} is raised. This includes situations where the
fa867d8ee7eb Remove some remaining {\rm ...} constructs.
Fred Drake <fdrake@acm.org>
parents: 9523
diff changeset
1101 operation is not defined for some reason, like \method{seek()} on a tty
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1102 device or writing a file opened for reading.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1103
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1104 Files have the following methods:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1105
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1106
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1107 \begin{methoddesc}[file]{close}{}
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1108 Close the file. A closed file cannot be read or written any more.
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1109 Any operation which requires that the file be open will raise a
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1110 \exception{ValueError} after the file has been closed. Calling
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1111 \method{close()} more than once is allowed.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1112 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1113
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1114 \begin{methoddesc}[file]{flush}{}
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1115 Flush the internal buffer, like \code{stdio}'s
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1116 \cfunction{fflush()}. This may be a no-op on some file-like
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1117 objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1118 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1119
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1120 \begin{methoddesc}[file]{isatty}{}
22920
2392af05f052 Update docs for bool changes by Guido around April 6
Neal Norwitz <nnorwitz@gmail.com>
parents: 22785
diff changeset
1121 Return \code{True} if the file is connected to a tty(-like) device, else
2392af05f052 Update docs for bool changes by Guido around April 6
Neal Norwitz <nnorwitz@gmail.com>
parents: 22785
diff changeset
1122 \code{False}. \note{If a file-like object is not associated
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1123 with a real file, this method should \emph{not} be implemented.}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1124 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1125
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1126 \begin{methoddesc}[file]{fileno}{}
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1127 \index{file descriptor}
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1128 \index{descriptor, file}
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1129 Return the integer ``file descriptor'' that is used by the
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1130 underlying implementation to request I/O operations from the
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1131 operating system. This can be useful for other, lower level
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1132 interfaces that use file descriptors, such as the
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1133 \refmodule{fcntl}\refbimodindex{fcntl} module or
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1134 \function{os.read()} and friends. \note{File-like objects
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1135 which do not have a real file descriptor should \emph{not} provide
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1136 this method!}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1137 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1138
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1139 \begin{methoddesc}[file]{read}{\optional{size}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1140 Read at most \var{size} bytes from the file (less if the read hits
10606
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1141 \EOF{} before obtaining \var{size} bytes). If the \var{size}
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1142 argument is negative or omitted, read all data until \EOF{} is
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1143 reached. The bytes are returned as a string object. An empty
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1144 string is returned when \EOF{} is encountered immediately. (For
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1145 certain files, like ttys, it makes sense to continue reading after
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1146 an \EOF{} is hit.) Note that this method may call the underlying
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1147 C function \cfunction{fread()} more than once in an effort to
fe5fcb7e73f7 Correct documentation for <file>.read(); Python makes a serious
Fred Drake <fdrake@acm.org>
parents: 10520
diff changeset
1148 acquire as close to \var{size} bytes as possible.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1149 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1150
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1151 \begin{methoddesc}[file]{readline}{\optional{size}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1152 Read one entire line from the file. A trailing newline character is
10520
7ee1e3134147 Fixed latex2html weirdness with footnotes.
Fred Drake <fdrake@acm.org>
parents: 10241
diff changeset
1153 kept in the string\footnote{
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1154 The advantage of leaving the newline on is that
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1155 returning an empty string is then an unambiguous \EOF{}
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1156 indication. It is also possible (in cases where it might
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1157 matter, for example, if you
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1158 want to make an exact copy of a file while scanning its lines)
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1159 to tell whether the last line of a file ended in a newline
13933
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
1160 or not (yes this happens!).
4d14eef8ea07 Added Marc-Andre Lemburg's documentation for string methods, with some
Fred Drake <fdrake@acm.org>
parents: 13894
diff changeset
1161 } (but may be absent when a file ends with an
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1162 incomplete line). If the \var{size} argument is present and
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1163 non-negative, it is a maximum byte count (including the trailing
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1164 newline) and an incomplete line may be returned.
23860
63ee31bb25f3 Make a start at describing the results of class/type unification
Steve Holden <steve@holdenweb.com>
parents: 23847
diff changeset
1165 An empty string is returned \emph{only} when \EOF{} is encountered
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1166 immediately. \note{Unlike \code{stdio}'s \cfunction{fgets()}, the
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1167 returned string contains null characters (\code{'\e 0'}) if they
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1168 occurred in the input.}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1169 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1170
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1171 \begin{methoddesc}[file]{readlines}{\optional{sizehint}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1172 Read until \EOF{} using \method{readline()} and return a list containing
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1173 the lines thus read. If the optional \var{sizehint} argument is
21062
bc02c3b09626 Clean up some markup cruft. A number of the macros that take no
Fred Drake <fdrake@acm.org>
parents: 20767
diff changeset
1174 present, instead of reading up to \EOF, whole lines totalling
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1175 approximately \var{sizehint} bytes (possibly after rounding up to an
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1176 internal buffer size) are read. Objects implementing a file-like
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1177 interface may choose to ignore \var{sizehint} if it cannot be
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1178 implemented, or cannot be implemented efficiently.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1179 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1180
15926
ac13cef423c8 Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents: 15896
diff changeset
1181 \begin{methoddesc}[file]{xreadlines}{}
17612
c19d6db6e99b Only document <file>.xreadlines() once; added version annotation.
Fred Drake <fdrake@acm.org>
parents: 17603
diff changeset
1182 Equivalent to
c19d6db6e99b Only document <file>.xreadlines() once; added version annotation.
Fred Drake <fdrake@acm.org>
parents: 17603
diff changeset
1183 \function{xreadlines.xreadlines(\var{file})}.\refstmodindex{xreadlines}
c19d6db6e99b Only document <file>.xreadlines() once; added version annotation.
Fred Drake <fdrake@acm.org>
parents: 17603
diff changeset
1184 (See the \refmodule{xreadlines} module for more information.)
c19d6db6e99b Only document <file>.xreadlines() once; added version annotation.
Fred Drake <fdrake@acm.org>
parents: 17603
diff changeset
1185 \versionadded{2.1}
15926
ac13cef423c8 Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents: 15896
diff changeset
1186 \end{methoddesc}
ac13cef423c8 Document xreadlines() method. (Forgot to check this in before!)
Guido van Rossum <guido@python.org>
parents: 15896
diff changeset
1187
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1188 \begin{methoddesc}[file]{seek}{offset\optional{, whence}}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1189 Set the file's current position, like \code{stdio}'s \cfunction{fseek()}.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1190 The \var{whence} argument is optional and defaults to \code{0}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1191 (absolute file positioning); other values are \code{1} (seek
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1192 relative to the current position) and \code{2} (seek relative to the
15731
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1193 file's end). There is no return value. Note that if the file is
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1194 opened for appending (mode \code{'a'} or \code{'a+'}), any
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1195 \method{seek()} operations will be undone at the next write. If the
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1196 file is only opened for writing in append mode (mode \code{'a'}),
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1197 this method is essentially a no-op, but it remains useful for files
a06415994cb5 Added information about the interaction of opening a file in append mode
Fred Drake <fdrake@acm.org>
parents: 15522
diff changeset
1198 opened in append mode with reading enabled (mode \code{'a+'}).
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1199 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1200
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1201 \begin{methoddesc}[file]{tell}{}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1202 Return the file's current position, like \code{stdio}'s
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1203 \cfunction{ftell()}.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1204 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1205
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1206 \begin{methoddesc}[file]{truncate}{\optional{size}}
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1207 Truncate the file's size. If the optional \var{size} argument is
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1208 present, the file is truncated to (at most) that size. The size
22241
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1209 defaults to the current position. The current file position is
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1210 not changed. Note that if a specified size exceeds the file's
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1211 current size, the result is platform-dependent: possibilities
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1212 include that file may remain unchanged, increase to the specified
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1213 size as if zero-filled, or increase to the specified size with
7584b6f1afde Change Windows file.truncate() to (a) restore the original file position,
Tim Peters <tim.peters@gmail.com>
parents: 22214
diff changeset
1214 undefined new content.
22214
e24ba04d01b0 file_truncate(): provide full "large file" support on Windows, by
Tim Peters <tim.peters@gmail.com>
parents: 21542
diff changeset
1215 Availability: Windows, many \UNIX variants.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1216 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1217
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1218 \begin{methoddesc}[file]{write}{str}
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1219 Write a string to the file. There is no return value. Due to
15789
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1220 buffering, the string may not actually show up in the file until
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1221 the \method{flush()} or \method{close()} method is called.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1222 \end{methoddesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1223
20045
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1224 \begin{methoddesc}[file]{writelines}{sequence}
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1225 Write a sequence of strings to the file. The sequence can be any
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1226 iterable object producing strings, typically a list of strings.
7b8c11739714 Generalize file.writelines() to allow iterable objects.
Tim Peters <tim.peters@gmail.com>
parents: 20031
diff changeset
1227 There is no return value.
15789
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1228 (The name is intended to match \method{readlines()};
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1229 \method{writelines()} does not add line separators.)
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1230 \end{methoddesc}
9e9556924b0a Added documentation for the xreadlines module & related changes. The
Fred Drake <fdrake@acm.org>
parents: 15731
diff changeset
1231
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1232
20031
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1233 Files support the iterator protocol. Each iteration returns the same
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1234 result as \code{\var{file}.readline()}, and iteration ends when the
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1235 \method{readline()} method returns an empty string.
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1236
e5a3f9d7766b Note that files are iterable; describe what the iterator returns.
Fred Drake <fdrake@acm.org>
parents: 19529
diff changeset
1237
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1238 File objects also offer a number of other interesting attributes.
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1239 These are not required for file-like objects, but should be
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1240 implemented if they make sense for the particular object.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1241
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1242 \begin{memberdesc}[file]{closed}
22920
2392af05f052 Update docs for bool changes by Guido around April 6
Neal Norwitz <nnorwitz@gmail.com>
parents: 22785
diff changeset
1243 bool indicating the current state of the file object. This is a
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1244 read-only attribute; the \method{close()} method changes the value.
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1245 It may not be available on all file-like objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1246 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1247
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1248 \begin{memberdesc}[file]{mode}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1249 The I/O mode for the file. If the file was created using the
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1250 \function{open()} built-in function, this will be the value of the
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1251 \var{mode} parameter. This is a read-only attribute and may not be
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1252 present on all file-like objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1253 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1254
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1255 \begin{memberdesc}[file]{name}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1256 If the file object was created using \function{open()}, the name of
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1257 the file. Otherwise, some string that indicates the source of the
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1258 file object, of the form \samp{<\mbox{\ldots}>}. This is a read-only
14685
faf3e734254d Clarify a number of issues about the file-like object API based on
Fred Drake <fdrake@acm.org>
parents: 14557
diff changeset
1259 attribute and may not be present on all file-like objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1260 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1261
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1262 \begin{memberdesc}[file]{softspace}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1263 Boolean that indicates whether a space character needs to be printed
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1264 before another value when using the \keyword{print} statement.
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1265 Classes that are trying to simulate a file object should also have a
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1266 writable \member{softspace} attribute, which should be initialized to
14485
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1267 zero. This will be automatic for most classes implemented in Python
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1268 (care may be needed for objects that override attribute access); types
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1269 implemented in C will have to provide a writable
ac0246586d52 Improve a couple of references to the language reference, making them
Fred Drake <fdrake@acm.org>
parents: 14044
diff changeset
1270 \member{softspace} attribute.
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1271 \note{This attribute is not used to control the
14705
4712f5b8f279 Clarify that the softspace attribute is used by print for state management,
Fred Drake <fdrake@acm.org>
parents: 14685
diff changeset
1272 \keyword{print} statement, but to allow the implementation of
20580
376ee174ecd0 Use the \note and \warning macros where appropriate.
Fred Drake <fdrake@acm.org>
parents: 20173
diff changeset
1273 \keyword{print} to keep track of its internal state.}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1274 \end{memberdesc}
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1275
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1276
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1277 \subsection{Other Built-in Types \label{typesother}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1278
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1279 The interpreter supports several other kinds of objects.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1280 Most of these support only one or two operations.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1281
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1282
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1283 \subsubsection{Modules \label{typesmodules}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1284
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1285 The only special operation on a module is attribute access:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1286 \code{\var{m}.\var{name}}, where \var{m} is a module and \var{name}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1287 accesses a name defined in \var{m}'s symbol table. Module attributes
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1288 can be assigned to. (Note that the \keyword{import} statement is not,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1289 strictly speaking, an operation on a module object; \code{import
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1290 \var{foo}} does not require a module object named \var{foo} to exist,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1291 rather it requires an (external) \emph{definition} for a module named
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1292 \var{foo} somewhere.)
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1293
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1294 A special member of every module is \member{__dict__}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1295 This is the dictionary containing the module's symbol table.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1296 Modifying this dictionary will actually change the module's symbol
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1297 table, but direct assignment to the \member{__dict__} attribute is not
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1298 possible (you can write \code{\var{m}.__dict__['a'] = 1}, which
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1299 defines \code{\var{m}.a} to be \code{1}, but you can't write
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1300 \code{\var{m}.__dict__ = \{\}}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1301
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1302 Modules built into the interpreter are written like this:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1303 \code{<module 'sys' (built-in)>}. If loaded from a file, they are
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1304 written as \code{<module 'os' from
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1305 '/usr/local/lib/python\shortversion/os.pyc'>}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1306
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1307
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1308 \subsubsection{Classes and Class Instances \label{typesobjects}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1309 \nodename{Classes and Instances}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1310
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1311 See chapters 3 and 7 of the \citetitle[../ref/ref.html]{Python
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1312 Reference Manual} for these.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1313
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1314
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1315 \subsubsection{Functions \label{typesfunctions}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1316
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1317 Function objects are created by function definitions. The only
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1318 operation on a function object is to call it:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1319 \code{\var{func}(\var{argument-list})}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1320
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1321 There are really two flavors of function objects: built-in functions
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1322 and user-defined functions. Both support the same operation (to call
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1323 the function), but the implementation is different, hence the
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1324 different object types.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1325
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1326 The implementation adds two special read-only attributes:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1327 \code{\var{f}.func_code} is a function's \dfn{code
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1328 object}\obindex{code} (see below) and \code{\var{f}.func_globals} is
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1329 the dictionary used as the function's global namespace (this is the
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1330 same as \code{\var{m}.__dict__} where \var{m} is the module in which
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1331 the function \var{f} was defined).
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1332
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1333 Function objects also support getting and setting arbitrary
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1334 attributes, which can be used to, e.g. attach metadata to functions.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1335 Regular attribute dot-notation is used to get and set such
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1336 attributes. \emph{Note that the current implementation only supports
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1337 function attributes on user-defined functions. Function attributes on
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1338 built-in functions may be supported in the future.}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1339
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1340 Functions have another special attribute \code{\var{f}.__dict__}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1341 (a.k.a. \code{\var{f}.func_dict}) which contains the namespace used to
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1342 support function attributes. \code{__dict__} and \code{func_dict} can
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1343 be accessed directly or set to a dictionary object. A function's
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1344 dictionary cannot be deleted.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1345
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1346 \subsubsection{Methods \label{typesmethods}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1347 \obindex{method}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1348
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1349 Methods are functions that are called using the attribute notation.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1350 There are two flavors: built-in methods (such as \method{append()} on
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1351 lists) and class instance methods. Built-in methods are described
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1352 with the types that support them.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1353
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1354 The implementation adds two special read-only attributes to class
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1355 instance methods: \code{\var{m}.im_self} is the object on which the
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1356 method operates, and \code{\var{m}.im_func} is the function
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1357 implementing the method. Calling \code{\var{m}(\var{arg-1},
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1358 \var{arg-2}, \textrm{\ldots}, \var{arg-n})} is completely equivalent to
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1359 calling \code{\var{m}.im_func(\var{m}.im_self, \var{arg-1},
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1360 \var{arg-2}, \textrm{\ldots}, \var{arg-n})}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1361
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1362 Class instance methods are either \emph{bound} or \emph{unbound},
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1363 referring to whether the method was accessed through an instance or a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1364 class, respectively. When a method is unbound, its \code{im_self}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1365 attribute will be \code{None} and if called, an explicit \code{self}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1366 object must be passed as the first argument. In this case,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1367 \code{self} must be an instance of the unbound method's class (or a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1368 subclass of that class), otherwise a \code{TypeError} is raised.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1369
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1370 Like function objects, methods objects support getting
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1371 arbitrary attributes. However, since method attributes are actually
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1372 stored on the underlying function object (\code{meth.im_func}),
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1373 setting method attributes on either bound or unbound methods is
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1374 disallowed. Attempting to set a method attribute results in a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1375 \code{TypeError} being raised. In order to set a method attribute,
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1376 you need to explicitly set it on the underlying function object:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1377
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1378 \begin{verbatim}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1379 class C:
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1380 def method(self):
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1381 pass
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1382
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1383 c = C()
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1384 c.method.im_func.whoami = 'my name is c'
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1385 \end{verbatim}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1386
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1387 See the \citetitle[../ref/ref.html]{Python Reference Manual} for more
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1388 information.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1389
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1390
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1391 \subsubsection{Code Objects \label{bltin-code-objects}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1392 \obindex{code}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1393
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1394 Code objects are used by the implementation to represent
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1395 ``pseudo-compiled'' executable Python code such as a function body.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1396 They differ from function objects because they don't contain a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1397 reference to their global execution environment. Code objects are
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1398 returned by the built-in \function{compile()} function and can be
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1399 extracted from function objects through their \member{func_code}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1400 attribute.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1401 \bifuncindex{compile}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1402 \withsubitem{(function object attribute)}{\ttindex{func_code}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1403
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1404 A code object can be executed or evaluated by passing it (instead of a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1405 source string) to the \keyword{exec} statement or the built-in
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1406 \function{eval()} function.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1407 \stindex{exec}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1408 \bifuncindex{eval}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1409
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1410 See the \citetitle[../ref/ref.html]{Python Reference Manual} for more
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1411 information.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1412
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1413
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1414 \subsubsection{Type Objects \label{bltin-type-objects}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1415
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1416 Type objects represent the various object types. An object's type is
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1417 accessed by the built-in function \function{type()}. There are no special
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1418 operations on types. The standard module \module{types} defines names
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1419 for all standard built-in types.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1420 \bifuncindex{type}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1421 \refstmodindex{types}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1422
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1423 Types are written like this: \code{<type 'int'>}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1424
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1425
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1426 \subsubsection{The Null Object \label{bltin-null-object}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1427
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1428 This object is returned by functions that don't explicitly return a
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1429 value. It supports no special operations. There is exactly one null
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1430 object, named \code{None} (a built-in name).
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1431
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1432 It is written as \code{None}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1433
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1434
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1435 \subsubsection{The Ellipsis Object \label{bltin-ellipsis-object}}
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1436
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1437 This object is used by extended slice notation (see the
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1438 \citetitle[../ref/ref.html]{Python Reference Manual}). It supports no
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1439 special operations. There is exactly one ellipsis object, named
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1440 \constant{Ellipsis} (a built-in name).
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1441
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1442 It is written as \code{Ellipsis}.
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1443
22785
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1444 \subsubsection{Boolean Values}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1445
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1446 Boolean values are the two constant objects \code{False} and
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1447 \code{True}. They are used to represent truth values (although other
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1448 values can also be considered false or true). In numeric contexts
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1449 (for example when used as the argument to an arithmetic operator),
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1450 they behave like the integers 0 and 1, respectively. The built-in
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1451 function \function{bool()} can be used to cast any value to a Boolean,
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1452 if the value can be interpreted as a truth value (see section Truth
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1453 Value Testing above).
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1454
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1455 They are written as \code{False} and \code{True}, respectively.
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1456 \index{False}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1457 \index{True}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1458 \indexii{Boolean}{values}
aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in
Guido van Rossum <guido@python.org>
parents: 22241
diff changeset
1459
20767
b3f48c5d6e16 Promote file objects out of the "Other Objects" category, so they become
Fred Drake <fdrake@acm.org>
parents: 20764
diff changeset
1460
10156
0f7d694bc334 Make sure all HTML pages generated from this section have reasonable
Fred Drake <fdrake@acm.org>
parents: 10147
diff changeset
1461 \subsubsection{Internal Objects \label{typesinternal}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1462
11463
17e12305973e Use \citetitle and \programopt as appropriate.
Fred Drake <fdrake@acm.org>
parents: 11183
diff changeset
1463 See the \citetitle[../ref/ref.html]{Python Reference Manual} for this
14044
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
1464 information. It describes stack frame objects, traceback objects, and
a905c5aa0691 As pointed out by Denis S. Otkidach <den@analyt.chem.msu.ru>, xrange()
Fred Drake <fdrake@acm.org>
parents: 13967
diff changeset
1465 slice objects.
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1466
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1467
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
1468 \subsection{Special Attributes \label{specialattrs}}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1469
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1470 The implementation adds a few special read-only attributes to several
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1471 object types, where they are relevant:
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1472
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1473 \begin{memberdesc}[object]{__dict__}
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1474 A dictionary or other mapping object used to store an
9083
bc41e86c938c Markup nits.
Fred Drake <fdrake@acm.org>
parents: 9034
diff changeset
1475 object's (writable) attributes.
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1476 \end{memberdesc}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1477
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1478 \begin{memberdesc}[object]{__methods__}
21159
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
Fred Drake <fdrake@acm.org>
parents: 21062
diff changeset
1479 \deprecated{2.2}{Use the built-in function \function{dir()} to get a
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
Fred Drake <fdrake@acm.org>
parents: 21062
diff changeset
1480 list of an object's attributes. This attribute is no longer available.}
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1481 \end{memberdesc}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1482
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1483 \begin{memberdesc}[object]{__members__}
21159
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
Fred Drake <fdrake@acm.org>
parents: 21062
diff changeset
1484 \deprecated{2.2}{Use the built-in function \function{dir()} to get a
6fa96b329e15 Remove most references to __members__ and __methods__, leaving only one pair
Fred Drake <fdrake@acm.org>
parents: 21062
diff changeset
1485 list of an object's attributes. This attribute is no longer available.}
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1486 \end{memberdesc}
8730
8a306dfd9f33 Move files around to get the names to match the module names except for
Fred Drake <fdrake@acm.org>
parents:
diff changeset
1487
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1488 \begin{memberdesc}[instance]{__class__}
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1489 The class to which a class instance belongs.
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1490 \end{memberdesc}
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1491
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1492 \begin{memberdesc}[class]{__bases__}
18416
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1493 The tuple of base classes of a class object. If there are no base
33b4357aebb8 Fix up a few style nits -- avoid "e.g." and "i.e." -- these make
Fred Drake <fdrake@acm.org>
parents: 18395
diff changeset
1494 classes, this will be an empty tuple.
15383
eeb7c8a5b79f Document the proper exception to be raised by I/O operations on closed
Fred Drake <fdrake@acm.org>
parents: 15332
diff changeset
1495 \end{memberdesc}