cpython-lru_cache-weakref: Doc/tutorial/interpreter.rst annotate

annotate Doc/tutorial/interpreter.rst @ 74135:9c19df6c8ea0 3.2

News entry for Issue12798

author	Senthil Kumaran <senthil@uthcode.com>
date	Fri, 23 Dec 2011 11:11:21 +0800
parents	7a2877d12d52
children	d2df5bc89fc9 6b5a58836dae

rev	line source
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	1 .. _tut-using:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	2
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	3 ****************************
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	4 Using the Python Interpreter
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	5 ****************************
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	6
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	7
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	8 .. _tut-invoking:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	9
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	10 Invoking the Interpreter
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	11 ========================
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	12
54872 a24f09606b83 bump to 3.2a0 Benjamin Peterson <benjamin@python.org> parents: 50514 diff changeset	13 The Python interpreter is usually installed as :file:`/usr/local/bin/python3.2`
48894 03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	14 on those machines where it is available; putting :file:`/usr/local/bin` in your
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	15 Unix shell's search path makes it possible to start it by typing the command ::
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	16
54872 a24f09606b83 bump to 3.2a0 Benjamin Peterson <benjamin@python.org> parents: 50514 diff changeset	17 python3.2
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	18
48894 03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	19 to the shell. [#]_ Since the choice of the directory where the interpreter lives
03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	20 is an installation option, other places are possible; check with your local
03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	21 Python guru or system administrator. (E.g., :file:`/usr/local/python` is a
03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	22 popular alternative location.)
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	23
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	24 On Windows machines, the Python installation is usually placed in
54872 a24f09606b83 bump to 3.2a0 Benjamin Peterson <benjamin@python.org> parents: 50514 diff changeset	25 :file:`C:\\Python32`, though you can change this when you're running the
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	26 installer. To add this directory to your path, you can type the following
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	27 command into the command prompt in a DOS box::
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	28
54872 a24f09606b83 bump to 3.2a0 Benjamin Peterson <benjamin@python.org> parents: 50514 diff changeset	29 set path=%path%;C:\python32
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	30
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	31 Typing an end-of-file character (:kbd:`Control-D` on Unix, :kbd:`Control-Z` on
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	32 Windows) at the primary prompt causes the interpreter to exit with a zero exit
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	33 status. If that doesn't work, you can exit the interpreter by typing the
56368 c9bd62efe6ce Merged revisions 75231 via svnmerge from Benjamin Peterson <benjamin@python.org> parents: 56062 diff changeset	34 following command: ``quit()``.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	35
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	36 The interpreter's line-editing features usually aren't very sophisticated. On
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	37 Unix, whoever installed the interpreter may have enabled support for the GNU
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	38 readline library, which adds more elaborate interactive editing and history
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	39 features. Perhaps the quickest check to see whether command line editing is
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	40 supported is typing Control-P to the first Python prompt you get. If it beeps,
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	41 you have command line editing; see Appendix :ref:`tut-interacting` for an
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	42 introduction to the keys. If nothing appears to happen, or if ``^P`` is echoed,
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	43 command line editing isn't available; you'll only be able to use backspace to
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	44 remove characters from the current line.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	45
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	46 The interpreter operates somewhat like the Unix shell: when called with standard
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	47 input connected to a tty device, it reads and executes commands interactively;
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	48 when called with a file name argument or with a file as standard input, it reads
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	49 and executes a script from that file.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	50
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	51 A second way of starting the interpreter is ``python -c command [arg] ...``,
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	52 which executes the statement(s) in command, analogous to the shell's
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	53 :option:`-c` option. Since Python statements often contain spaces or other
47557 98827a21e352 Merged revisions 63724,63726,63732,63744,63754-63755,63757-63758,63760,63775,63781-63782,63787,63805-63808,63818-63819,63823-63824 via svnmerge from Georg Brandl <georg@python.org> parents: 44834 diff changeset	54 characters that are special to the shell, it is usually advised to quote
98827a21e352 Merged revisions 63724,63726,63732,63744,63754-63755,63757-63758,63760,63775,63781-63782,63787,63805-63808,63818-63819,63823-63824 via svnmerge from Georg Brandl <georg@python.org> parents: 44834 diff changeset	55 command in its entirety with single quotes.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	56
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	57 Some Python modules are also useful as scripts. These can be invoked using
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	58 ``python -m module [arg] ...``, which executes the source file for module as
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	59 if you had spelled out its full name on the command line.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	60
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	61 When a script file is used, it is sometimes useful to be able to run the script
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	62 and enter interactive mode afterwards. This can be done by passing :option:`-i`
73251 7a2877d12d52 remove confusing paragraph (as part of r87523); thanks to AJ Hill from docs@ Sandro Tosi <sandro.tosi@gmail.com> parents: 71778 diff changeset	63 before the script.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	64
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	65
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	66 .. _tut-argpassing:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	67
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	68 Argument Passing
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	69 ----------------
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	70
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	71 When known to the interpreter, the script name and additional arguments
67917 8084c668b637 Merged revisions 87136,87221,87256,87337-87338,87571,87839,88164 via svnmerge from R. David Murray <rdmurray@bitdance.com> parents: 56368 diff changeset	72 thereafter are turned into a list of strings and assigned to the ``argv``
8084c668b637 Merged revisions 87136,87221,87256,87337-87338,87571,87839,88164 via svnmerge from R. David Murray <rdmurray@bitdance.com> parents: 56368 diff changeset	73 variable in the ``sys`` module. You can access this list by executing ``import
8084c668b637 Merged revisions 87136,87221,87256,87337-87338,87571,87839,88164 via svnmerge from R. David Murray <rdmurray@bitdance.com> parents: 56368 diff changeset	74 sys``. The length of the list is at least one; when no script and no arguments
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	75 are given, ``sys.argv[0]`` is an empty string. When the script name is given as
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	76 ``'-'`` (meaning standard input), ``sys.argv[0]`` is set to ``'-'``. When
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	77 :option:`-c` command is used, ``sys.argv[0]`` is set to ``'-c'``. When
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	78 :option:`-m` module is used, ``sys.argv[0]`` is set to the full name of the
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	79 located module. Options found after :option:`-c` command or :option:`-m`
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	80 module are not consumed by the Python interpreter's option processing but
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	81 left in ``sys.argv`` for the command or module to handle.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	82
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	83
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	84 .. _tut-interactive:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	85
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	86 Interactive Mode
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	87 ----------------
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	88
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	89 When commands are read from a tty, the interpreter is said to be in *interactive
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	90 mode. In this mode it prompts for the next command with the primary prompt*,
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	91 usually three greater-than signs (``>>>``); for continuation lines it prompts
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	92 with the secondary prompt, by default three dots (``...``). The interpreter
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	93 prints a welcome message stating its version number and a copyright notice
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	94 before printing the first prompt::
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	95
56061 5a1e879832fe #6935: update version. Georg Brandl <georg@python.org> parents: 54872 diff changeset	96 $ python3.2
5a1e879832fe #6935: update version. Georg Brandl <georg@python.org> parents: 54872 diff changeset	97 Python 3.2 (py3k, Sep 12 2007, 12:21:02)
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	98 [GCC 3.4.6 20060404 (Red Hat 3.4.6-8)] on linux2
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	99 Type "help", "copyright", "credits" or "license" for more information.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	100 >>>
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	101
56062 9817915ebdeb #6935: update version. Georg Brandl <georg@python.org> parents: 50514 diff changeset	102 .. XXX update for new releases
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	103
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	104 Continuation lines are needed when entering a multi-line construct. As an
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	105 example, take a look at this :keyword:`if` statement::
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	106
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	107 >>> the_world_is_flat = 1
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	108 >>> if the_world_is_flat:
43219 655071bf6c45 Convert all print statements in the docs. Georg Brandl <georg@python.org> parents: 42604 diff changeset	109 ... print("Be careful not to fall off!")
50514 c3d3b760d8bf Remove trailing whitespace. Georg Brandl <georg@python.org> parents: 49946 diff changeset	110 ...
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	111 Be careful not to fall off!
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	112
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	113
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	114 .. _tut-interp:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	115
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	116 The Interpreter and Its Environment
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	117 ===================================
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	118
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	119
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	120 .. _tut-error:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	121
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	122 Error Handling
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	123 --------------
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	124
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	125 When an error occurs, the interpreter prints an error message and a stack trace.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	126 In interactive mode, it then returns to the primary prompt; when input came from
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	127 a file, it exits with a nonzero exit status after printing the stack trace.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	128 (Exceptions handled by an :keyword:`except` clause in a :keyword:`try` statement
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	129 are not errors in this context.) Some errors are unconditionally fatal and
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	130 cause an exit with a nonzero exit; this applies to internal inconsistencies and
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	131 some cases of running out of memory. All error messages are written to the
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	132 standard error stream; normal output from executed commands is written to
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	133 standard output.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	134
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	135 Typing the interrupt character (usually Control-C or DEL) to the primary or
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	136 secondary prompt cancels the input and returns to the primary prompt. [#]_
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	137 Typing an interrupt while a command is executing raises the
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	138 :exc:`KeyboardInterrupt` exception, which may be handled by a :keyword:`try`
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	139 statement.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	140
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	141
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	142 .. _tut-scripts:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	143
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	144 Executable Python Scripts
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	145 -------------------------
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	146
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	147 On BSD'ish Unix systems, Python scripts can be made directly executable, like
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	148 shell scripts, by putting the line ::
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	149
60758 cea38ef60700 Update the python version in the interpreter tutorial. Ezio Melotti <ezio.melotti@gmail.com> parents: 56367 diff changeset	150 #! /usr/bin/env python3.2
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	151
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	152 (assuming that the interpreter is on the user's :envvar:`PATH`) at the beginning
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	153 of the script and giving the file an executable mode. The ``#!`` must be the
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	154 first two characters of the file. On some platforms, this first line must end
49186 47db62bf6aa7 Merged revisions 66452 via svnmerge from Georg Brandl <georg@python.org> parents: 48894 diff changeset	155 with a Unix-style line ending (``'\n'``), not a Windows (``'\r\n'``) line
47db62bf6aa7 Merged revisions 66452 via svnmerge from Georg Brandl <georg@python.org> parents: 48894 diff changeset	156 ending. Note that the hash, or pound, character, ``'#'``, is used to start a
47db62bf6aa7 Merged revisions 66452 via svnmerge from Georg Brandl <georg@python.org> parents: 48894 diff changeset	157 comment in Python.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	158
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	159 The script can be given an executable mode, or permission, using the
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	160 :program:`chmod` command::
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	161
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	162 $ chmod +x myscript.py
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	163
44834 ed33da2e74e7 Merged revisions 60143-60149 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44396 diff changeset	164 On Windows systems, there is no notion of an "executable mode". The Python
ed33da2e74e7 Merged revisions 60143-60149 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44396 diff changeset	165 installer automatically associates ``.py`` files with ``python.exe`` so that
ed33da2e74e7 Merged revisions 60143-60149 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44396 diff changeset	166 a double-click on a Python file will run it as a script. The extension can
ed33da2e74e7 Merged revisions 60143-60149 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44396 diff changeset	167 also be ``.pyw``, in that case, the console window that normally appears is
ed33da2e74e7 Merged revisions 60143-60149 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44396 diff changeset	168 suppressed.
ed33da2e74e7 Merged revisions 60143-60149 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44396 diff changeset	169
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	170
70795 9bfaa723a194 Add missing reST target to one heading in the tutorial Éric Araujo <merwok@netwok.org> parents: 68257 diff changeset	171 .. _tut-source-encoding:
9bfaa723a194 Add missing reST target to one heading in the tutorial Éric Araujo <merwok@netwok.org> parents: 68257 diff changeset	172
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	173 Source Code Encoding
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	174 --------------------
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	175
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	176 By default, Python source files are treated as encoded in UTF-8. In that
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	177 encoding, characters of most languages in the world can be used simultaneously
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	178 in string literals, identifiers and comments --- although the standard library
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	179 only uses ASCII characters for identifiers, a convention that any portable code
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	180 should follow. To display all these characters properly, your editor must
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	181 recognize that the file is UTF-8, and it must use a font that supports all the
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	182 characters in the file.
43219 655071bf6c45 Convert all print statements in the docs. Georg Brandl <georg@python.org> parents: 42604 diff changeset	183
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	184 It is also possible to specify a different encoding for source files. In order
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	185 to do this, put one more special comment line right after the ``#!`` line to
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	186 define the source file encoding::
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	187
50514 c3d3b760d8bf Remove trailing whitespace. Georg Brandl <georg@python.org> parents: 49946 diff changeset	188 # -- coding: encoding --
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	189
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	190 With that declaration, everything in the source file will be treated as having
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	191 the encoding encoding instead of UTF-8. The list of possible encodings can be
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	192 found in the Python Library Reference, in the section on :mod:`codecs`.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	193
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	194 For example, if your editor of choice does not support UTF-8 encoded files and
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	195 insists on using some other encoding, say Windows-1252, you can write::
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	196
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	197 # -- coding: cp-1252 --
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	198
43449 7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	199 and still use all characters in the Windows-1252 character set in the source
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	200 files. The special encoding comment must be in the first or second line
7fcd9945d1bf #1211, #1212, #1213: py3k fixes to the tutorial. Georg Brandl <georg@python.org> parents: 43219 diff changeset	201 within the file.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	202
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	203
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	204 .. _tut-startup:
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	205
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	206 The Interactive Startup File
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	207 ----------------------------
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	208
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	209 When you use Python interactively, it is frequently handy to have some standard
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	210 commands executed every time the interpreter is started. You can do this by
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	211 setting an environment variable named :envvar:`PYTHONSTARTUP` to the name of a
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	212 file containing your start-up commands. This is similar to the :file:`.profile`
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	213 feature of the Unix shells.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	214
44396 6556f3f22c19 Merged revisions 59605-59624 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43449 diff changeset	215 .. XXX This should probably be dumped in an appendix, since most people
6556f3f22c19 Merged revisions 59605-59624 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43449 diff changeset	216 don't use Python interactively in non-trivial ways.
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	217
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	218 This file is only read in interactive sessions, not when Python reads commands
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	219 from a script, and not when :file:`/dev/tty` is given as the explicit source of
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	220 commands (which otherwise behaves like an interactive session). It is executed
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	221 in the same namespace where interactive commands are executed, so that objects
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	222 that it defines or imports can be used without qualification in the interactive
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	223 session. You can also change the prompts ``sys.ps1`` and ``sys.ps2`` in this
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	224 file.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	225
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	226 If you want to read an additional start-up file from the current directory, you
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	227 can program this in the global start-up file using code like ``if
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	228 os.path.isfile('.pythonrc.py'): exec(open('.pythonrc.py').read())``.
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	229 If you want to use the startup file in a script, you must do this explicitly
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	230 in the script::
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	231
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	232 import os
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	233 filename = os.environ.get('PYTHONSTARTUP')
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	234 if filename and os.path.isfile(filename):
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	235 exec(open(filename).read())
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	236
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	237
71778 74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	238 .. _tut-customize:
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	239
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	240 The Customization Modules
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	241 -------------------------
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	242
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	243 Python provides two hooks to let you customize it: :mod:`sitecustomize` and
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	244 :mod:`usercustomize`. To see how it works, you need first to find the location
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	245 of your user site-packages directory. Start Python and run this code:
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	246
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	247 >>> import site
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	248 >>> site.getusersitepackages()
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	249 '/home/user/.local/lib/python3.2/site-packages'
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	250
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	251 Now you can create a file named :file:`usercustomize.py` in that directory and
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	252 put anything you want in it. It will affect every invocation of Python, unless
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	253 it is started with the :option:`-s` option to disable the automatic import.
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	254
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	255 :mod:`sitecustomize` works in the same way, but is typically created by an
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	256 administrator of the computer in the global site-packages directory, and is
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	257 imported before :mod:`usercustomize`. See the documentation of the :mod:`site`
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	258 module for more details.
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	259
74179a79d673 Improve documentation for PEP 370 support in site module (#8617). Éric Araujo <merwok@netwok.org> parents: 70795 diff changeset	260
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	261 .. rubric:: Footnotes
9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	262
56062 9817915ebdeb #6935: update version. Georg Brandl <georg@python.org> parents: 50514 diff changeset	263 .. [#] On Unix, the Python 3.x interpreter is by default not installed with the
48894 03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	264 executable named ``python``, so that it does not conflict with a
03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	265 simultaneously installed Python 2.x executable.
03e216dc8fec #3577: 3.0 is not installed as "python" on Unix. Georg Brandl <georg@python.org> parents: 47557 diff changeset	266
42604 9e1529bf0442 Move the 3k reST doc tree in place. Georg Brandl <georg@python.org> parents: diff changeset	267 .. [#] A problem with the GNU Readline package may prevent this.

Mercurial > cpython-lru_cache-weakref

annotate Doc/tutorial/interpreter.rst @ 74135:9c19df6c8ea0 3.2