cpython-lru_cache-weakref: Lib/difflib.py annotate

annotate Lib/difflib.py @ 29384:2d39ec0e55aa legacy-trunk

For the context and unified diff functions: * Simplified test for visible changes * Improved variable names and line spacing * Replaced dict(a=3) style with Py2.2 compatable {'a':3}

author	Raymond Hettinger <python@rcn.com>
date	Sun, 08 Jun 2003 19:38:42 +0000
parents	15f1dc5b7ddc
children	94ac1d42a420

rev	line source
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1 #! /usr/bin/env python
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	2
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	3 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	4 Module difflib -- helpers for computing deltas between objects.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	5
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	6 Function get_close_matches(word, possibilities, n=3, cutoff=0.6):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	7 Use SequenceMatcher to return list of the best "good enough" matches.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	8
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	9 Function context_diff(a, b):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	10 For two lists of strings, return a delta in context diff format.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	11
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	12 Function ndiff(a, b):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	13 Return a delta: the difference between `a` and `b` (lists of strings).
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	14
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	15 Function restore(delta, which):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	16 Return one of the two sequences that generated an ndiff delta.
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	17
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	18 Function unified_diff(a, b):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	19 For two lists of strings, return a delta in unified diff format.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	20
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	21 Class SequenceMatcher:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	22 A flexible class for comparing pairs of sequences of any type.
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	23
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	24 Class Differ:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	25 For producing human-readable deltas from sequences of lines of text.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	26 """
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	27
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	28 __all__ = ['get_close_matches', 'ndiff', 'restore', 'SequenceMatcher',
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	29 'Differ','IS_CHARACTER_JUNK', 'IS_LINE_JUNK', 'context_diff',
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	30 'unified_diff']
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	31
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	32 class SequenceMatcher:
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	33
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	34 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	35 SequenceMatcher is a flexible class for comparing pairs of sequences of
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	36 any type, so long as the sequence elements are hashable. The basic
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	37 algorithm predates, and is a little fancier than, an algorithm
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	38 published in the late 1980's by Ratcliff and Obershelp under the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	39 hyperbolic name "gestalt pattern matching". The basic idea is to find
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	40 the longest contiguous matching subsequence that contains no "junk"
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	41 elements (R-O doesn't address junk). The same idea is then applied
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	42 recursively to the pieces of the sequences to the left and to the right
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	43 of the matching subsequence. This does not yield minimal edit
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	44 sequences, but does tend to yield matches that "look right" to people.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	45
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	46 SequenceMatcher tries to compute a "human-friendly diff" between two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	47 sequences. Unlike e.g. UNIX(tm) diff, the fundamental notion is the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	48 longest contiguous & junk-free matching subsequence. That's what
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	49 catches peoples' eyes. The Windows(tm) windiff has another interesting
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	50 notion, pairing up elements that appear uniquely in each sequence.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	51 That, and the method here, appear to yield more intuitive difference
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	52 reports than does diff. This method appears to be the least vulnerable
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	53 to synching up on blocks of "junk lines", though (like blank lines in
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	54 ordinary text files, or maybe "<P>" lines in HTML files). That may be
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	55 because this is the only method of the 3 that has a concept of
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	56 "junk" <wink>.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	57
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	58 Example, comparing two strings, and considering blanks to be "junk":
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	59
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	60 >>> s = SequenceMatcher(lambda x: x == " ",
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	61 ... "private Thread currentThread;",
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	62 ... "private volatile Thread currentThread;")
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	63 >>>
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	64
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	65 .ratio() returns a float in [0, 1], measuring the "similarity" of the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	66 sequences. As a rule of thumb, a .ratio() value over 0.6 means the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	67 sequences are close matches:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	68
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	69 >>> print round(s.ratio(), 3)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	70 0.866
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	71 >>>
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	72
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	73 If you're only interested in where the sequences match,
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	74 .get_matching_blocks() is handy:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	75
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	76 >>> for block in s.get_matching_blocks():
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	77 ... print "a[%d] and b[%d] match for %d elements" % block
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	78 a[0] and b[0] match for 8 elements
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	79 a[8] and b[17] match for 6 elements
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	80 a[14] and b[23] match for 15 elements
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	81 a[29] and b[38] match for 0 elements
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	82
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	83 Note that the last tuple returned by .get_matching_blocks() is always a
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	84 dummy, (len(a), len(b), 0), and this is the only case in which the last
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	85 tuple element (number of elements matched) is 0.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	86
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	87 If you want to know how to change the first sequence into the second,
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	88 use .get_opcodes():
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	89
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	90 >>> for opcode in s.get_opcodes():
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	91 ... print "%6s a[%d:%d] b[%d:%d]" % opcode
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	92 equal a[0:8] b[0:8]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	93 insert a[8:8] b[8:17]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	94 equal a[8:14] b[17:23]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	95 equal a[14:29] b[23:38]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	96
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	97 See the Differ class for a fancy human-friendly file differencer, which
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	98 uses SequenceMatcher both to compare sequences of lines, and to compare
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	99 sequences of characters within similar (near-matching) lines.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	100
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	101 See also function get_close_matches() in this module, which shows how
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	102 simple code building on SequenceMatcher can be used to do useful work.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	103
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	104 Timing: Basic R-O is cubic time worst case and quadratic time expected
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	105 case. SequenceMatcher is quadratic time for the worst case and has
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	106 expected-case behavior dependent in a complicated way on how many
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	107 elements the sequences have in common; best case time is linear.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	108
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	109 Methods:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	110
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	111 __init__(isjunk=None, a='', b='')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	112 Construct a SequenceMatcher.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	113
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	114 set_seqs(a, b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	115 Set the two sequences to be compared.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	116
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	117 set_seq1(a)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	118 Set the first sequence to be compared.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	119
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	120 set_seq2(b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	121 Set the second sequence to be compared.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	122
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	123 find_longest_match(alo, ahi, blo, bhi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	124 Find longest matching block in a[alo:ahi] and b[blo:bhi].
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	125
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	126 get_matching_blocks()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	127 Return list of triples describing matching subsequences.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	128
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	129 get_opcodes()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	130 Return list of 5-tuples describing how to turn a into b.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	131
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	132 ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	133 Return a measure of the sequences' similarity (float in [0,1]).
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	134
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	135 quick_ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	136 Return an upper bound on .ratio() relatively quickly.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	137
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	138 real_quick_ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	139 Return an upper bound on ratio() very quickly.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	140 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	141
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	142 def __init__(self, isjunk=None, a='', b=''):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	143 """Construct a SequenceMatcher.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	144
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	145 Optional arg isjunk is None (the default), or a one-argument
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	146 function that takes a sequence element and returns true iff the
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	147 element is junk. None is equivalent to passing "lambda x: 0", i.e.
16695 e14c5f34fa05 Fix a few small typos in the docstrings. Fred Drake <fdrake@acm.org> parents: 16551 diff changeset	148 no elements are considered to be junk. For example, pass
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	149 lambda x: x in " \\t"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	150 if you're comparing lines as sequences of characters, and don't
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	151 want to synch up on blanks or hard tabs.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	152
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	153 Optional arg a is the first of two sequences to be compared. By
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	154 default, an empty string. The elements of a must be hashable. See
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	155 also .set_seqs() and .set_seq1().
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	156
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	157 Optional arg b is the second of two sequences to be compared. By
16695 e14c5f34fa05 Fix a few small typos in the docstrings. Fred Drake <fdrake@acm.org> parents: 16551 diff changeset	158 default, an empty string. The elements of b must be hashable. See
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	159 also .set_seqs() and .set_seq2().
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	160 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	161
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	162 # Members:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	163 # a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	164 # first sequence
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	165 # b
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	166 # second sequence; differences are computed as "what do
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	167 # we need to do to 'a' to change it into 'b'?"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	168 # b2j
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	169 # for x in b, b2j[x] is a list of the indices (into b)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	170 # at which x appears; junk elements do not appear
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	171 # fullbcount
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	172 # for x in b, fullbcount[x] == the number of times x
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	173 # appears in b; only materialized if really needed (used
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	174 # only for computing quick_ratio())
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	175 # matching_blocks
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	176 # a list of (i, j, k) triples, where a[i:i+k] == b[j:j+k];
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	177 # ascending & non-overlapping in i and in j; terminated by
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	178 # a dummy (len(a), len(b), 0) sentinel
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	179 # opcodes
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	180 # a list of (tag, i1, i2, j1, j2) tuples, where tag is
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	181 # one of
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	182 # 'replace' a[i1:i2] should be replaced by b[j1:j2]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	183 # 'delete' a[i1:i2] should be deleted
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	184 # 'insert' b[j1:j2] should be inserted
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	185 # 'equal' a[i1:i2] == b[j1:j2]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	186 # isjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	187 # a user-supplied function taking a sequence element and
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	188 # returning true iff the element is "junk" -- this has
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	189 # subtle but helpful effects on the algorithm, which I'll
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	190 # get around to writing up someday <0.9 wink>.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	191 # DON'T USE! Only __chain_b uses this. Use isbjunk.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	192 # isbjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	193 # for x in b, isbjunk(x) == isjunk(x) but much faster;
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	194 # it's really the has_key method of a hidden dict.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	195 # DOES NOT WORK for x in a!
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	196 # isbpopular
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	197 # for x in b, isbpopular(x) is true iff b is reasonably long
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	198 # (at least 200 elements) and x accounts for more than 1% of
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	199 # its elements. DOES NOT WORK for x in a!
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	200
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	201 self.isjunk = isjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	202 self.a = self.b = None
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	203 self.set_seqs(a, b)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	204
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	205 def set_seqs(self, a, b):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	206 """Set the two sequences to be compared.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	207
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	208 >>> s = SequenceMatcher()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	209 >>> s.set_seqs("abcd", "bcde")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	210 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	211 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	212 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	213
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	214 self.set_seq1(a)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	215 self.set_seq2(b)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	216
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	217 def set_seq1(self, a):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	218 """Set the first sequence to be compared.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	219
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	220 The second sequence to be compared is not changed.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	221
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	222 >>> s = SequenceMatcher(None, "abcd", "bcde")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	223 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	224 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	225 >>> s.set_seq1("bcde")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	226 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	227 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	228 >>>
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	229
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	230 SequenceMatcher computes and caches detailed information about the
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	231 second sequence, so if you want to compare one sequence S against
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	232 many sequences, use .set_seq2(S) once and call .set_seq1(x)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	233 repeatedly for each of the other sequences.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	234
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	235 See also set_seqs() and set_seq2().
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	236 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	237
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	238 if a is self.a:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	239 return
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	240 self.a = a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	241 self.matching_blocks = self.opcodes = None
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	242
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	243 def set_seq2(self, b):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	244 """Set the second sequence to be compared.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	245
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	246 The first sequence to be compared is not changed.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	247
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	248 >>> s = SequenceMatcher(None, "abcd", "bcde")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	249 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	250 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	251 >>> s.set_seq2("abcd")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	252 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	253 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	254 >>>
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	255
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	256 SequenceMatcher computes and caches detailed information about the
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	257 second sequence, so if you want to compare one sequence S against
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	258 many sequences, use .set_seq2(S) once and call .set_seq1(x)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	259 repeatedly for each of the other sequences.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	260
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	261 See also set_seqs() and set_seq1().
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	262 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	263
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	264 if b is self.b:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	265 return
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	266 self.b = b
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	267 self.matching_blocks = self.opcodes = None
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	268 self.fullbcount = None
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	269 self.__chain_b()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	270
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	271 # For each element x in b, set b2j[x] to a list of the indices in
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	272 # b where x appears; the indices are in increasing order; note that
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	273 # the number of times x appears in b is len(b2j[x]) ...
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	274 # when self.isjunk is defined, junk elements don't show up in this
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	275 # map at all, which stops the central find_longest_match method
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	276 # from starting any matching block at a junk element ...
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	277 # also creates the fast isbjunk function ...
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	278 # b2j also does not contain entries for "popular" elements, meaning
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	279 # elements that account for more than 1% of the total elements, and
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	280 # when the sequence is reasonably large (>= 200 elements); this can
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	281 # be viewed as an adaptive notion of semi-junk, and yields an enormous
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	282 # speedup when, e.g., comparing program files with hundreds of
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	283 # instances of "return NULL;" ...
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	284 # note that this is only called when b changes; so for cross-product
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	285 # kinds of matches, it's best to call set_seq2 once, then set_seq1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	286 # repeatedly
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	287
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	288 def __chain_b(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	289 # Because isjunk is a user-defined (not C) function, and we test
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	290 # for junk a LOT, it's important to minimize the number of calls.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	291 # Before the tricks described here, __chain_b was by far the most
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	292 # time-consuming routine in the whole module! If anyone sees
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	293 # Jim Roskind, thank him again for profile.py -- I never would
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	294 # have guessed that.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	295 # The first trick is to build b2j ignoring the possibility
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	296 # of junk. I.e., we don't call isjunk at all yet. Throwing
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	297 # out the junk later is much cheaper than building b2j "right"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	298 # from the start.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	299 b = self.b
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	300 n = len(b)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	301 self.b2j = b2j = {}
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	302 populardict = {}
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	303 for i, elt in enumerate(b):
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	304 if elt in b2j:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	305 indices = b2j[elt]
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	306 if n >= 200 and len(indices) * 100 > n:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	307 populardict[elt] = 1
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	308 del indices[:]
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	309 else:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	310 indices.append(i)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	311 else:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	312 b2j[elt] = [i]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	313
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	314 # Purge leftover indices for popular elements.
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	315 for elt in populardict:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	316 del b2j[elt]
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	317
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	318 # Now b2j.keys() contains elements uniquely, and especially when
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	319 # the sequence is a string, that's usually a good deal smaller
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	320 # than len(string). The difference is the number of isjunk calls
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	321 # saved.
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	322 isjunk = self.isjunk
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	323 junkdict = {}
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	324 if isjunk:
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	325 for d in populardict, b2j:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	326 for elt in d.keys():
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	327 if isjunk(elt):
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	328 junkdict[elt] = 1
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	329 del d[elt]
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	330
23620 a1de0bab5475 SF 563203. Replaced 'has_key()' with 'in'. Raymond Hettinger <python@rcn.com> parents: 23300 diff changeset	331 # Now for x in b, isjunk(x) == x in junkdict, but the
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	332 # latter is much faster. Note too that while there may be a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	333 # lot of junk in the sequence, the number of unique junk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	334 # elements is probably small. So the memory burden of keeping
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	335 # this dict alive is likely trivial compared to the size of b2j.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	336 self.isbjunk = junkdict.has_key
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	337 self.isbpopular = populardict.has_key
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	338
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	339 def find_longest_match(self, alo, ahi, blo, bhi):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	340 """Find longest matching block in a[alo:ahi] and b[blo:bhi].
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	341
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	342 If isjunk is not defined:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	343
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	344 Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	345 alo <= i <= i+k <= ahi
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	346 blo <= j <= j+k <= bhi
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	347 and for all (i',j',k') meeting those conditions,
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	348 k >= k'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	349 i <= i'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	350 and if i == i', j <= j'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	351
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	352 In other words, of all maximal matching blocks, return one that
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	353 starts earliest in a, and of all those maximal matching blocks that
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	354 start earliest in a, return the one that starts earliest in b.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	355
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	356 >>> s = SequenceMatcher(None, " abcd", "abcd abcd")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	357 >>> s.find_longest_match(0, 5, 0, 9)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	358 (0, 4, 5)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	359
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	360 If isjunk is defined, first the longest matching block is
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	361 determined as above, but with the additional restriction that no
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	362 junk element appears in the block. Then that block is extended as
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	363 far as possible by matching (only) junk elements on both sides. So
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	364 the resulting block never matches on junk except as identical junk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	365 happens to be adjacent to an "interesting" match.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	366
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	367 Here's the same example as before, but considering blanks to be
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	368 junk. That prevents " abcd" from matching the " abcd" at the tail
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	369 end of the second sequence directly. Instead only the "abcd" can
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	370 match, and matches the leftmost "abcd" in the second sequence:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	371
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	372 >>> s = SequenceMatcher(lambda x: x==" ", " abcd", "abcd abcd")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	373 >>> s.find_longest_match(0, 5, 0, 9)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	374 (1, 0, 4)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	375
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	376 If no blocks match, return (alo, blo, 0).
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	377
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	378 >>> s = SequenceMatcher(None, "ab", "c")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	379 >>> s.find_longest_match(0, 2, 0, 1)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	380 (0, 0, 0)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	381 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	382
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	383 # CAUTION: stripping common prefix or suffix would be incorrect.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	384 # E.g.,
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	385 # ab
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	386 # acab
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	387 # Longest matching block is "ab", but if common prefix is
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	388 # stripped, it's "a" (tied with "b"). UNIX(tm) diff does so
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	389 # strip, so ends up claiming that ab is changed to acab by
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	390 # inserting "ca" in the middle. That's minimal but unintuitive:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	391 # "it's obvious" that someone inserted "ac" at the front.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	392 # Windiff ends up at the same place as diff, but by pairing up
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	393 # the unique 'b's and then matching the first two 'a's.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	394
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	395 a, b, b2j, isbjunk = self.a, self.b, self.b2j, self.isbjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	396 besti, bestj, bestsize = alo, blo, 0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	397 # find longest junk-free match
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	398 # during an iteration of the loop, j2len[j] = length of longest
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	399 # junk-free match ending with a[i-1] and b[j]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	400 j2len = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	401 nothing = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	402 for i in xrange(alo, ahi):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	403 # look at all instances of a[i] in b; note that because
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	404 # b2j has no junk keys, the loop is skipped if a[i] is junk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	405 j2lenget = j2len.get
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	406 newj2len = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	407 for j in b2j.get(a[i], nothing):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	408 # a[i] matches b[j]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	409 if j < blo:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	410 continue
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	411 if j >= bhi:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	412 break
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	413 k = newj2len[j] = j2lenget(j-1, 0) + 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	414 if k > bestsize:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	415 besti, bestj, bestsize = i-k+1, j-k+1, k
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	416 j2len = newj2len
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	417
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	418 # Extend the best by non-junk elements on each end. In particular,
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	419 # "popular" non-junk elements aren't in b2j, which greatly speeds
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	420 # the inner loop above, but also means "the best" match so far
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	421 # doesn't contain any junk or popular non-junk elements.
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	422 while besti > alo and bestj > blo and \
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	423 not isbjunk(b[bestj-1]) and \
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	424 a[besti-1] == b[bestj-1]:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	425 besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	426 while besti+bestsize < ahi and bestj+bestsize < bhi and \
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	427 not isbjunk(b[bestj+bestsize]) and \
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	428 a[besti+bestsize] == b[bestj+bestsize]:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	429 bestsize += 1
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	430
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	431 # Now that we have a wholly interesting match (albeit possibly
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	432 # empty!), we may as well suck up the matching junk on each
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	433 # side of it too. Can't think of a good reason not to, and it
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	434 # saves post-processing the (possibly considerable) expense of
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	435 # figuring out what to do with it. In the case of an empty
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	436 # interesting match, this is clearly the right thing to do,
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	437 # because no other kind of match is possible in the regions.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	438 while besti > alo and bestj > blo and \
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	439 isbjunk(b[bestj-1]) and \
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	440 a[besti-1] == b[bestj-1]:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	441 besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	442 while besti+bestsize < ahi and bestj+bestsize < bhi and \
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	443 isbjunk(b[bestj+bestsize]) and \
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	444 a[besti+bestsize] == b[bestj+bestsize]:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	445 bestsize = bestsize + 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	446
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	447 return besti, bestj, bestsize
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	448
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	449 def get_matching_blocks(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	450 """Return list of triples describing matching subsequences.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	451
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	452 Each triple is of the form (i, j, n), and means that
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	453 a[i:i+n] == b[j:j+n]. The triples are monotonically increasing in
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	454 i and in j.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	455
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	456 The last triple is a dummy, (len(a), len(b), 0), and is the only
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	457 triple with n==0.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	458
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	459 >>> s = SequenceMatcher(None, "abxcd", "abcd")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	460 >>> s.get_matching_blocks()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	461 [(0, 0, 2), (3, 2, 2), (5, 4, 0)]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	462 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	463
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	464 if self.matching_blocks is not None:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	465 return self.matching_blocks
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	466 self.matching_blocks = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	467 la, lb = len(self.a), len(self.b)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	468 self.__helper(0, la, 0, lb, self.matching_blocks)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	469 self.matching_blocks.append( (la, lb, 0) )
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	470 return self.matching_blocks
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	471
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	472 # builds list of matching blocks covering a[alo:ahi] and
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	473 # b[blo:bhi], appending them in increasing order to answer
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	474
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	475 def __helper(self, alo, ahi, blo, bhi, answer):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	476 i, j, k = x = self.find_longest_match(alo, ahi, blo, bhi)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	477 # a[alo:i] vs b[blo:j] unknown
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	478 # a[i:i+k] same as b[j:j+k]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	479 # a[i+k:ahi] vs b[j+k:bhi] unknown
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	480 if k:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	481 if alo < i and blo < j:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	482 self.__helper(alo, i, blo, j, answer)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	483 answer.append(x)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	484 if i+k < ahi and j+k < bhi:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	485 self.__helper(i+k, ahi, j+k, bhi, answer)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	486
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	487 def get_opcodes(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	488 """Return list of 5-tuples describing how to turn a into b.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	489
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	490 Each tuple is of the form (tag, i1, i2, j1, j2). The first tuple
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	491 has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	492 tuple preceding it, and likewise for j1 == the previous j2.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	493
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	494 The tags are strings, with these meanings:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	495
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	496 'replace': a[i1:i2] should be replaced by b[j1:j2]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	497 'delete': a[i1:i2] should be deleted.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	498 Note that j1==j2 in this case.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	499 'insert': b[j1:j2] should be inserted at a[i1:i1].
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	500 Note that i1==i2 in this case.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	501 'equal': a[i1:i2] == b[j1:j2]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	502
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	503 >>> a = "qabxcd"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	504 >>> b = "abycdf"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	505 >>> s = SequenceMatcher(None, a, b)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	506 >>> for tag, i1, i2, j1, j2 in s.get_opcodes():
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	507 ... print ("%7s a[%d:%d] (%s) b[%d:%d] (%s)" %
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	508 ... (tag, i1, i2, a[i1:i2], j1, j2, b[j1:j2]))
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	509 delete a[0:1] (q) b[0:0] ()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	510 equal a[1:3] (ab) b[0:2] (ab)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	511 replace a[3:4] (x) b[2:3] (y)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	512 equal a[4:6] (cd) b[3:5] (cd)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	513 insert a[6:6] () b[5:6] (f)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	514 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	515
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	516 if self.opcodes is not None:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	517 return self.opcodes
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	518 i = j = 0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	519 self.opcodes = answer = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	520 for ai, bj, size in self.get_matching_blocks():
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	521 # invariant: we've pumped out correct diffs to change
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	522 # a[:i] into b[:j], and the next matching block is
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	523 # a[ai:ai+size] == b[bj:bj+size]. So we need to pump
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	524 # out a diff to change a[i:ai] into b[j:bj], pump out
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	525 # the matching block, and move (i,j) beyond the match
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	526 tag = ''
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	527 if i < ai and j < bj:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	528 tag = 'replace'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	529 elif i < ai:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	530 tag = 'delete'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	531 elif j < bj:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	532 tag = 'insert'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	533 if tag:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	534 answer.append( (tag, i, ai, j, bj) )
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	535 i, j = ai+size, bj+size
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	536 # the list of matching blocks is terminated by a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	537 # sentinel with size 0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	538 if size:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	539 answer.append( ('equal', ai, i, bj, j) )
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	540 return answer
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	541
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	542 def get_grouped_opcodes(self, n=3):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	543 """ Isolate change clusters by eliminating ranges with no changes.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	544
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	545 Return a generator of groups with upto n lines of context.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	546 Each group is in the same format as returned by get_opcodes().
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	547
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	548 >>> from pprint import pprint
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	549 >>> a = map(str, range(1,40))
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	550 >>> b = a[:]
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	551 >>> b[8:8] = ['i'] # Make an insertion
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	552 >>> b[20] += 'x' # Make a replacement
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	553 >>> b[23:28] = [] # Make a deletion
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	554 >>> b[30] += 'y' # Make another replacement
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	555 >>> pprint(list(SequenceMatcher(None,a,b).get_grouped_opcodes()))
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	556 [[('equal', 5, 8, 5, 8), ('insert', 8, 8, 8, 9), ('equal', 8, 11, 9, 12)],
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	557 [('equal', 16, 19, 17, 20),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	558 ('replace', 19, 20, 20, 21),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	559 ('equal', 20, 22, 21, 23),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	560 ('delete', 22, 27, 23, 23),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	561 ('equal', 27, 30, 23, 26)],
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	562 [('equal', 31, 34, 27, 30),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	563 ('replace', 34, 35, 30, 31),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	564 ('equal', 35, 38, 31, 34)]]
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	565 """
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	566
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	567 codes = self.get_opcodes()
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	568 # Fixup leading and trailing groups if they show no changes.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	569 if codes[0][0] == 'equal':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	570 tag, i1, i2, j1, j2 = codes[0]
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	571 codes[0] = tag, max(i1, i2-n), i2, max(j1, j2-n), j2
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	572 if codes[-1][0] == 'equal':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	573 tag, i1, i2, j1, j2 = codes[-1]
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	574 codes[-1] = tag, i1, min(i2, i1+n), j1, min(j2, j1+n)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	575
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	576 nn = n + n
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	577 group = []
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	578 for tag, i1, i2, j1, j2 in codes:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	579 # End the current group and start a new one whenever
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	580 # there is a large range with no changes.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	581 if tag == 'equal' and i2-i1 > nn:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	582 group.append((tag, i1, min(i2, i1+n), j1, min(j2, j1+n)))
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	583 yield group
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	584 group = []
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	585 i1, j1 = max(i1, i2-n), max(j1, j2-n)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	586 group.append((tag, i1, i2, j1 ,j2))
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	587 if group and not (len(group)==1 and group[0][0] == 'equal'):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	588 yield group
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	589
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	590 def ratio(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	591 """Return a measure of the sequences' similarity (float in [0,1]).
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	592
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	593 Where T is the total number of elements in both sequences, and
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	594 M is the number of matches, this is 2,0*M / T.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	595 Note that this is 1 if the sequences are identical, and 0 if
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	596 they have nothing in common.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	597
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	598 .ratio() is expensive to compute if you haven't already computed
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	599 .get_matching_blocks() or .get_opcodes(), in which case you may
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	600 want to try .quick_ratio() or .real_quick_ratio() first to get an
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	601 upper bound.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	602
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	603 >>> s = SequenceMatcher(None, "abcd", "bcde")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	604 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	605 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	606 >>> s.quick_ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	607 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	608 >>> s.real_quick_ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	609 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	610 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	611
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	612 matches = reduce(lambda sum, triple: sum + triple[-1],
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	613 self.get_matching_blocks(), 0)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	614 return 2.0 * matches / (len(self.a) + len(self.b))
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	615
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	616 def quick_ratio(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	617 """Return an upper bound on ratio() relatively quickly.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	618
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	619 This isn't defined beyond that it is an upper bound on .ratio(), and
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	620 is faster to compute.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	621 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	622
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	623 # viewing a and b as multisets, set matches to the cardinality
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	624 # of their intersection; this counts the number of matches
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	625 # without regard to order, so is clearly an upper bound
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	626 if self.fullbcount is None:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	627 self.fullbcount = fullbcount = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	628 for elt in self.b:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	629 fullbcount[elt] = fullbcount.get(elt, 0) + 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	630 fullbcount = self.fullbcount
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	631 # avail[x] is the number of times x appears in 'b' less the
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	632 # number of times we've seen it in 'a' so far ... kinda
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	633 avail = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	634 availhas, matches = avail.has_key, 0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	635 for elt in self.a:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	636 if availhas(elt):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	637 numb = avail[elt]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	638 else:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	639 numb = fullbcount.get(elt, 0)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	640 avail[elt] = numb - 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	641 if numb > 0:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	642 matches = matches + 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	643 return 2.0 * matches / (len(self.a) + len(self.b))
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	644
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	645 def real_quick_ratio(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	646 """Return an upper bound on ratio() very quickly.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	647
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	648 This isn't defined beyond that it is an upper bound on .ratio(), and
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	649 is faster to compute than either .ratio() or .quick_ratio().
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	650 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	651
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	652 la, lb = len(self.a), len(self.b)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	653 # can't have more matches than the number of elements in the
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	654 # shorter sequence
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	655 return 2.0 * min(la, lb) / (la + lb)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	656
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	657 def get_close_matches(word, possibilities, n=3, cutoff=0.6):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	658 """Use SequenceMatcher to return list of the best "good enough" matches.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	659
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	660 word is a sequence for which close matches are desired (typically a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	661 string).
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	662
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	663 possibilities is a list of sequences against which to match word
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	664 (typically a list of strings).
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	665
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	666 Optional arg n (default 3) is the maximum number of close matches to
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	667 return. n must be > 0.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	668
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	669 Optional arg cutoff (default 0.6) is a float in [0, 1]. Possibilities
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	670 that don't score at least that similar to word are ignored.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	671
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	672 The best (no more than n) matches among the possibilities are returned
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	673 in a list, sorted by similarity score, most similar first.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	674
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	675 >>> get_close_matches("appel", ["ape", "apple", "peach", "puppy"])
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	676 ['apple', 'ape']
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	677 >>> import keyword as _keyword
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	678 >>> get_close_matches("wheel", _keyword.kwlist)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	679 ['while']
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	680 >>> get_close_matches("apple", _keyword.kwlist)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	681 []
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	682 >>> get_close_matches("accept", _keyword.kwlist)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	683 ['except']
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	684 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	685
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	686 if not n > 0:
16695 e14c5f34fa05 Fix a few small typos in the docstrings. Fred Drake <fdrake@acm.org> parents: 16551 diff changeset	687 raise ValueError("n must be > 0: " + `n`)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	688 if not 0.0 <= cutoff <= 1.0:
16695 e14c5f34fa05 Fix a few small typos in the docstrings. Fred Drake <fdrake@acm.org> parents: 16551 diff changeset	689 raise ValueError("cutoff must be in [0.0, 1.0]: " + `cutoff`)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	690 result = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	691 s = SequenceMatcher()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	692 s.set_seq2(word)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	693 for x in possibilities:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	694 s.set_seq1(x)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	695 if s.real_quick_ratio() >= cutoff and \
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	696 s.quick_ratio() >= cutoff and \
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	697 s.ratio() >= cutoff:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	698 result.append((s.ratio(), x))
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	699 # Sort by score.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	700 result.sort()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	701 # Retain only the best n.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	702 result = result[-n:]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	703 # Move best-scorer to head of list.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	704 result.reverse()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	705 # Strip scores.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	706 return [x for score, x in result]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	707
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	708
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	709 def _count_leading(line, ch):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	710 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	711 Return number of `ch` characters at the start of `line`.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	712
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	713 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	714
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	715 >>> _count_leading(' abc', ' ')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	716 3
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	717 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	718
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	719 i, n = 0, len(line)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	720 while i < n and line[i] == ch:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	721 i += 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	722 return i
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	723
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	724 class Differ:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	725 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	726 Differ is a class for comparing sequences of lines of text, and
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	727 producing human-readable differences or deltas. Differ uses
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	728 SequenceMatcher both to compare sequences of lines, and to compare
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	729 sequences of characters within similar (near-matching) lines.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	730
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	731 Each line of a Differ delta begins with a two-letter code:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	732
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	733 '- ' line unique to sequence 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	734 '+ ' line unique to sequence 2
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	735 ' ' line common to both sequences
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	736 '? ' line not present in either input sequence
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	737
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	738 Lines beginning with '? ' attempt to guide the eye to intraline
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	739 differences, and were not present in either input sequence. These lines
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	740 can be confusing if the sequences contain tab characters.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	741
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	742 Note that Differ makes no claim to produce a minimal diff. To the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	743 contrary, minimal diffs are often counter-intuitive, because they synch
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	744 up anywhere possible, sometimes accidental matches 100 pages apart.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	745 Restricting synch points to contiguous matches preserves some notion of
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	746 locality, at the occasional cost of producing a longer diff.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	747
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	748 Example: Comparing two texts.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	749
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	750 First we set up the texts, sequences of individual single-line strings
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	751 ending with newlines (such sequences can also be obtained from the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	752 `readlines()` method of file-like objects):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	753
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	754 >>> text1 = ''' 1. Beautiful is better than ugly.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	755 ... 2. Explicit is better than implicit.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	756 ... 3. Simple is better than complex.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	757 ... 4. Complex is better than complicated.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	758 ... '''.splitlines(1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	759 >>> len(text1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	760 4
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	761 >>> text1[0][-1]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	762 '\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	763 >>> text2 = ''' 1. Beautiful is better than ugly.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	764 ... 3. Simple is better than complex.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	765 ... 4. Complicated is better than complex.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	766 ... 5. Flat is better than nested.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	767 ... '''.splitlines(1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	768
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	769 Next we instantiate a Differ object:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	770
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	771 >>> d = Differ()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	772
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	773 Note that when instantiating a Differ object we may pass functions to
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	774 filter out line and character 'junk'. See Differ.__init__ for details.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	775
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	776 Finally, we compare the two:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	777
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	778 >>> result = list(d.compare(text1, text2))
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	779
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	780 'result' is a list of strings, so let's pretty-print it:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	781
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	782 >>> from pprint import pprint as _pprint
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	783 >>> _pprint(result)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	784 [' 1. Beautiful is better than ugly.\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	785 '- 2. Explicit is better than implicit.\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	786 '- 3. Simple is better than complex.\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	787 '+ 3. Simple is better than complex.\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	788 '? ++\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	789 '- 4. Complex is better than complicated.\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	790 '? ^ ---- ^\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	791 '+ 4. Complicated is better than complex.\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	792 '? ++++ ^ ^\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	793 '+ 5. Flat is better than nested.\n']
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	794
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	795 As a single multi-line string it looks like this:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	796
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	797 >>> print ''.join(result),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	798 1. Beautiful is better than ugly.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	799 - 2. Explicit is better than implicit.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	800 - 3. Simple is better than complex.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	801 + 3. Simple is better than complex.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	802 ? ++
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	803 - 4. Complex is better than complicated.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	804 ? ^ ---- ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	805 + 4. Complicated is better than complex.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	806 ? ++++ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	807 + 5. Flat is better than nested.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	808
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	809 Methods:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	810
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	811 __init__(linejunk=None, charjunk=None)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	812 Construct a text differencer, with optional filters.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	813
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	814 compare(a, b)
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	815 Compare two sequences of lines; generate the resulting delta.
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	816 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	817
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	818 def __init__(self, linejunk=None, charjunk=None):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	819 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	820 Construct a text differencer, with optional filters.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	821
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	822 The two optional keyword parameters are for filter functions:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	823
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	824 - `linejunk`: A function that should accept a single string argument,
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	825 and return true iff the string is junk. The module-level function
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	826 `IS_LINE_JUNK` may be used to filter out lines without visible
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	827 characters, except for at most one splat ('#'). It is recommended
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	828 to leave linejunk None; as of Python 2.3, the underlying
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	829 SequenceMatcher class has grown an adaptive notion of "noise" lines
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	830 that's better than any static definition the author has ever been
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	831 able to craft.
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	832
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	833 - `charjunk`: A function that should accept a string of length 1. The
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	834 module-level function `IS_CHARACTER_JUNK` may be used to filter out
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	835 whitespace characters (a blank or tab; note: bad idea to include
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	836 newline in this!). Use of IS_CHARACTER_JUNK is recommended.
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	837 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	838
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	839 self.linejunk = linejunk
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	840 self.charjunk = charjunk
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	841
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	842 def compare(self, a, b):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	843 r"""
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	844 Compare two sequences of lines; generate the resulting delta.
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	845
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	846 Each sequence must contain individual single-line strings ending with
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	847 newlines. Such sequences can be obtained from the `readlines()` method
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	848 of file-like objects. The delta generated also consists of newline-
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	849 terminated strings, ready to be printed as-is via the writeline()
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	850 method of a file-like object.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	851
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	852 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	853
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	854 >>> print ''.join(Differ().compare('one\ntwo\nthree\n'.splitlines(1),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	855 ... 'ore\ntree\nemu\n'.splitlines(1))),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	856 - one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	857 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	858 + ore
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	859 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	860 - two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	861 - three
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	862 ? -
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	863 + tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	864 + emu
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	865 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	866
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	867 cruncher = SequenceMatcher(self.linejunk, a, b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	868 for tag, alo, ahi, blo, bhi in cruncher.get_opcodes():
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	869 if tag == 'replace':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	870 g = self._fancy_replace(a, alo, ahi, b, blo, bhi)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	871 elif tag == 'delete':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	872 g = self._dump('-', a, alo, ahi)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	873 elif tag == 'insert':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	874 g = self._dump('+', b, blo, bhi)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	875 elif tag == 'equal':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	876 g = self._dump(' ', a, alo, ahi)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	877 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	878 raise ValueError, 'unknown tag ' + `tag`
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	879
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	880 for line in g:
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	881 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	882
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	883 def _dump(self, tag, x, lo, hi):
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	884 """Generate comparison results for a same-tagged range."""
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	885 for i in xrange(lo, hi):
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	886 yield '%s %s' % (tag, x[i])
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	887
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	888 def _plain_replace(self, a, alo, ahi, b, blo, bhi):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	889 assert alo < ahi and blo < bhi
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	890 # dump the shorter block first -- reduces the burden on short-term
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	891 # memory if the blocks are of very different sizes
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	892 if bhi - blo < ahi - alo:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	893 first = self._dump('+', b, blo, bhi)
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	894 second = self._dump('-', a, alo, ahi)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	895 else:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	896 first = self._dump('-', a, alo, ahi)
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	897 second = self._dump('+', b, blo, bhi)
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	898
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	899 for g in first, second:
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	900 for line in g:
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	901 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	902
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	903 def _fancy_replace(self, a, alo, ahi, b, blo, bhi):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	904 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	905 When replacing one block of lines with another, search the blocks
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	906 for similar lines; the best-matching pair (if any) is used as a
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	907 synch point, and intraline difference marking is done on the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	908 similar pair. Lots of work, but often worth it.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	909
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	910 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	911
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	912 >>> d = Differ()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	913 >>> d._fancy_replace(['abcDefghiJkl\n'], 0, 1, ['abcdefGhijkl\n'], 0, 1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	914 >>> print ''.join(d.results),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	915 - abcDefghiJkl
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	916 ? ^ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	917 + abcdefGhijkl
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	918 ? ^ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	919 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	920
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	921 # don't synch up unless the lines have a similarity score of at
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	922 # least cutoff; best_ratio tracks the best score seen so far
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	923 best_ratio, cutoff = 0.74, 0.75
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	924 cruncher = SequenceMatcher(self.charjunk)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	925 eqi, eqj = None, None # 1st indices of equal lines (if any)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	926
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	927 # search for the pair that matches best without being identical
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	928 # (identical lines must be junk lines, & we don't want to synch up
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	929 # on junk -- unless we have to)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	930 for j in xrange(blo, bhi):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	931 bj = b[j]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	932 cruncher.set_seq2(bj)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	933 for i in xrange(alo, ahi):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	934 ai = a[i]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	935 if ai == bj:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	936 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	937 eqi, eqj = i, j
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	938 continue
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	939 cruncher.set_seq1(ai)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	940 # computing similarity is expensive, so use the quick
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	941 # upper bounds first -- have seen this speed up messy
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	942 # compares by a factor of 3.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	943 # note that ratio() is only expensive to compute the first
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	944 # time it's called on a sequence pair; the expensive part
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	945 # of the computation is cached by cruncher
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	946 if cruncher.real_quick_ratio() > best_ratio and \
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	947 cruncher.quick_ratio() > best_ratio and \
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	948 cruncher.ratio() > best_ratio:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	949 best_ratio, best_i, best_j = cruncher.ratio(), i, j
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	950 if best_ratio < cutoff:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	951 # no non-identical "pretty close" pair
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	952 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	953 # no identical pair either -- treat it as a straight replace
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	954 for line in self._plain_replace(a, alo, ahi, b, blo, bhi):
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	955 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	956 return
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	957 # no close pair, but an identical pair -- synch up on that
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	958 best_i, best_j, best_ratio = eqi, eqj, 1.0
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	959 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	960 # there's a close pair, so forget the identical pair (if any)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	961 eqi = None
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	962
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	963 # a[best_i] very similar to b[best_j]; eqi is None iff they're not
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	964 # identical
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	965
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	966 # pump out diffs from before the synch point
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	967 for line in self._fancy_helper(a, alo, best_i, b, blo, best_j):
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	968 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	969
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	970 # do intraline marking on the synch pair
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	971 aelt, belt = a[best_i], b[best_j]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	972 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	973 # pump out a '-', '?', '+', '?' quad for the synched lines
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	974 atags = btags = ""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	975 cruncher.set_seqs(aelt, belt)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	976 for tag, ai1, ai2, bj1, bj2 in cruncher.get_opcodes():
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	977 la, lb = ai2 - ai1, bj2 - bj1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	978 if tag == 'replace':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	979 atags += '^' * la
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	980 btags += '^' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	981 elif tag == 'delete':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	982 atags += '-' * la
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	983 elif tag == 'insert':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	984 btags += '+' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	985 elif tag == 'equal':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	986 atags += ' ' * la
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	987 btags += ' ' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	988 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	989 raise ValueError, 'unknown tag ' + `tag`
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	990 for line in self._qformat(aelt, belt, atags, btags):
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	991 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	992 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	993 # the synch pair is identical
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	994 yield ' ' + aelt
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	995
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	996 # pump out diffs from after the synch point
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	997 for line in self._fancy_helper(a, best_i+1, ahi, b, best_j+1, bhi):
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	998 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	999
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1000 def _fancy_helper(self, a, alo, ahi, b, blo, bhi):
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1001 g = []
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1002 if alo < ahi:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1003 if blo < bhi:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1004 g = self._fancy_replace(a, alo, ahi, b, blo, bhi)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1005 else:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1006 g = self._dump('-', a, alo, ahi)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1007 elif blo < bhi:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1008 g = self._dump('+', b, blo, bhi)
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1009
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1010 for line in g:
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1011 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1012
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1013 def _qformat(self, aline, bline, atags, btags):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1014 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1015 Format "?" output and deal with leading tabs.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1016
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1017 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1018
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1019 >>> d = Differ()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1020 >>> d._qformat('\tabcDefghiJkl\n', '\t\tabcdefGhijkl\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1021 ... ' ^ ^ ^ ', '+ ^ ^ ^ ')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1022 >>> for line in d.results: print repr(line)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1023 ...
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1024 '- \tabcDefghiJkl\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1025 '? \t ^ ^ ^\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1026 '+ \t\tabcdefGhijkl\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1027 '? \t ^ ^ ^\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1028 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1029
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1030 # Can hurt, but will probably help most of the time.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1031 common = min(_count_leading(aline, "\t"),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1032 _count_leading(bline, "\t"))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1033 common = min(common, _count_leading(atags[:common], " "))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1034 atags = atags[common:].rstrip()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1035 btags = btags[common:].rstrip()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1036
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1037 yield "- " + aline
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1038 if atags:
20240 5c4261e74478 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 20038 diff changeset	1039 yield "? %s%s\n" % ("\t" * common, atags)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1040
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1041 yield "+ " + bline
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1042 if btags:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1043 yield "? %s%s\n" % ("\t" * common, btags)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1044
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1045 # With respect to junk, an earlier version of ndiff simply refused to
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1046 # start a match with a junk element. The result was cases like this:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1047 # before: private Thread currentThread;
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1048 # after: private volatile Thread currentThread;
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1049 # If you consider whitespace to be junk, the longest contiguous match
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1050 # not starting with junk is "e Thread currentThread". So ndiff reported
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1051 # that "e volatil" was inserted between the 't' and the 'e' in "private".
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1052 # While an accurate view, to people that's absurd. The current version
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1053 # looks for matching blocks that are entirely junk-free, then extends the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1054 # longest one of those as far as possible but only with matching junk.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1055 # So now "currentThread" is matched, then extended to suck up the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1056 # preceding blank; then "private" is matched, and extended to suck up the
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1057 # following blank; then "Thread" is matched; and finally ndiff reports
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1058 # that "volatile " was inserted before "Thread". The only quibble
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1059 # remaining is that perhaps it was really the case that " volatile"
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1060 # was inserted after "private". I can live with that <wink>.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1061
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1062 import re
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1063
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1064 def IS_LINE_JUNK(line, pat=re.compile(r"\s#?\s$").match):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1065 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1066 Return 1 for ignorable line: iff `line` is blank or contains a single '#'.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1067
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1068 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1069
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1070 >>> IS_LINE_JUNK('\n')
22785 aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in Guido van Rossum <guido@python.org> parents: 22719 diff changeset	1071 True
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1072 >>> IS_LINE_JUNK(' # \n')
22785 aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in Guido van Rossum <guido@python.org> parents: 22719 diff changeset	1073 True
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1074 >>> IS_LINE_JUNK('hello\n')
22785 aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in Guido van Rossum <guido@python.org> parents: 22719 diff changeset	1075 False
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1076 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1077
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1078 return pat(line) is not None
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1079
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1080 def IS_CHARACTER_JUNK(ch, ws=" \t"):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1081 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1082 Return 1 for ignorable character: iff `ch` is a space or tab.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1083
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1084 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1085
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1086 >>> IS_CHARACTER_JUNK(' ')
22785 aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in Guido van Rossum <guido@python.org> parents: 22719 diff changeset	1087 True
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1088 >>> IS_CHARACTER_JUNK('\t')
22785 aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in Guido van Rossum <guido@python.org> parents: 22719 diff changeset	1089 True
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1090 >>> IS_CHARACTER_JUNK('\n')
22785 aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in Guido van Rossum <guido@python.org> parents: 22719 diff changeset	1091 False
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1092 >>> IS_CHARACTER_JUNK('x')
22785 aa8d59823add Add the 'bool' type and its values 'False' and 'True', as described in Guido van Rossum <guido@python.org> parents: 22719 diff changeset	1093 False
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1094 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1095
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1096 return ch in ws
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1097
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1098 del re
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1099
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1100
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1101 def unified_diff(a, b, fromfile='', tofile='', fromfiledate='',
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1102 tofiledate='', n=3, lineterm='\n'):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1103 r"""
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1104 Compare two sequences of lines; generate the delta as a unified diff.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1105
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1106 Unified diffs are a compact way of showing line changes and a few
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1107 lines of context. The number of context lines is set by 'n' which
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1108 defaults to three.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1109
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1110 By default, the diff control lines (those with *** or ---) are
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1111 created with a trailing newline. This is helpful so that inputs
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1112 created from file.readlines() result in diffs that are suitable for
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1113 file.writelines() since both the inputs and outputs have trailing
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1114 newlines.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1115
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1116 For inputs that do not have trailing newlines, set the lineterm
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1117 argument to "" so that the output will be uniformly newline free.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1118
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1119 The unidiff format normally has a header for filenames and modification
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1120 times. Any or all of these may be specified using strings for
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1121 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'. The modification
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1122 times are normally expressed in the format returned by time.ctime().
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1123
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1124 Example:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1125
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1126 >>> for line in unified_diff('one two three four'.split(),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1127 ... 'zero one tree four'.split(), 'Original', 'Current',
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1128 ... 'Sat Jan 26 23:30:50 1991', 'Fri Jun 06 10:20:52 2003',
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1129 ... lineterm=''):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1130 ... print line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1131 --- Original Sat Jan 26 23:30:50 1991
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1132 +++ Current Fri Jun 06 10:20:52 2003
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1133 @@ -1,4 +1,4 @@
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1134 +zero
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1135 one
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1136 -two
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1137 -three
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1138 +tree
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1139 four
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1140 """
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1141
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1142 started = False
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1143 for group in SequenceMatcher(None,a,b).get_grouped_opcodes(n):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1144 if not started:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1145 yield '--- %s %s%s' % (fromfile, fromfiledate, lineterm)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1146 yield '+++ %s %s%s' % (tofile, tofiledate, lineterm)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1147 started = True
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1148 i1, i2, j1, j2 = group[0][1], group[-1][2], group[0][3], group[-1][4]
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1149 yield "@@ -%d,%d +%d,%d @@%s" % (i1+1, i2-i1, j1+1, j2-j1, lineterm)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1150 for tag, i1, i2, j1, j2 in group:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1151 if tag == 'equal':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1152 for line in a[i1:i2]:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1153 yield ' ' + line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1154 continue
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1155 if tag == 'replace' or tag == 'delete':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1156 for line in a[i1:i2]:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1157 yield '-' + line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1158 if tag == 'replace' or tag == 'insert':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1159 for line in b[j1:j2]:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1160 yield '+' + line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1161
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1162 # See http://www.unix.org/single_unix_specification/
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1163 def context_diff(a, b, fromfile='', tofile='',
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1164 fromfiledate='', tofiledate='', n=3, lineterm='\n'):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1165 r"""
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1166 Compare two sequences of lines; generate the delta as a context diff.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1167
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1168 Context diffs are a compact way of showing line changes and a few
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1169 lines of context. The number of context lines is set by 'n' which
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1170 defaults to three.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1171
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1172 By default, the diff control lines (those with *** or ---) are
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1173 created with a trailing newline. This is helpful so that inputs
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1174 created from file.readlines() result in diffs that are suitable for
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1175 file.writelines() since both the inputs and outputs have trailing
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1176 newlines.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1177
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1178 For inputs that do not have trailing newlines, set the lineterm
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1179 argument to "" so that the output will be uniformly newline free.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1180
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1181 The context diff format normally has a header for filenames and
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1182 modification times. Any or all of these may be specified using
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1183 strings for 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1184 The modification times are normally expressed in the format returned
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1185 by time.ctime(). If not specified, the strings default to blanks.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1186
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1187 Example:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1188
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1189 >>> print ''.join(context_diff('one\ntwo\nthree\nfour\n'.splitlines(1),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1190 ... 'zero\none\ntree\nfour\n'.splitlines(1), 'Original', 'Current',
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1191 ... 'Sat Jan 26 23:30:50 1991', 'Fri Jun 06 10:22:46 2003')),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1192 *** Original Sat Jan 26 23:30:50 1991
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1193 --- Current Fri Jun 06 10:22:46 2003
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1194 ***************
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1195 * 1,4 **
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1196 one
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1197 ! two
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1198 ! three
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1199 four
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1200 --- 1,4 ----
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1201 + zero
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1202 one
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1203 ! tree
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1204 four
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1205 """
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1206
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1207 started = False
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1208 prefixmap = {'insert':'+ ', 'delete':'- ', 'replace':'! ', 'equal':' '}
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1209 for group in SequenceMatcher(None,a,b).get_grouped_opcodes(n):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1210 if not started:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1211 yield '*** %s %s%s' % (fromfile, fromfiledate, lineterm)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1212 yield '--- %s %s%s' % (tofile, tofiledate, lineterm)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1213 started = True
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1214
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1215 yield '***************%s' % (lineterm,)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1216 if group[-1][2] - group[0][1] >= 2:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1217 yield '* %d,%d **%s' % (group[0][1]+1, group[-1][2], lineterm)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1218 else:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1219 yield '* %d **%s' % (group[-1][2], lineterm)
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1220 visiblechanges = [e for e in group if e[0] in ('replace', 'delete')]
2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1221 if visiblechanges:
2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1222 for tag, i1, i2, _, _ in group:
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1223 if tag != 'insert':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1224 for line in a[i1:i2]:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1225 yield prefixmap[tag] + line
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1226
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1227 if group[-1][4] - group[0][3] >= 2:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1228 yield '--- %d,%d ----%s' % (group[0][3]+1, group[-1][4], lineterm)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1229 else:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1230 yield '--- %d ----%s' % (group[-1][4], lineterm)
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1231 visiblechanges = [e for e in group if e[0] in ('replace', 'insert')]
2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1232 if visiblechanges:
2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1233 for tag, _, _, j1, j2 in group:
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1234 if tag != 'delete':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1235 for line in b[j1:j2]:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1236 yield prefixmap[tag] + line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1237
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	1238 def ndiff(a, b, linejunk=None, charjunk=IS_CHARACTER_JUNK):
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1239 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1240 Compare `a` and `b` (lists of strings); return a `Differ`-style delta.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1241
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1242 Optional keyword parameters `linejunk` and `charjunk` are for filter
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1243 functions (or None):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1244
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1245 - linejunk: A function that should accept a single string argument, and
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	1246 return true iff the string is junk. The default is None, and is
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	1247 recommended; as of Python 2.3, an adaptive notion of "noise" lines is
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	1248 used that does a good job on its own.
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1249
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1250 - charjunk: A function that should accept a string of length 1. The
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1251 default is module-level function IS_CHARACTER_JUNK, which filters out
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1252 whitespace characters (a blank or tab; note: bad idea to include newline
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1253 in this!).
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1254
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1255 Tools/scripts/ndiff.py is a command-line front-end to this function.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1256
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1257 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1258
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1259 >>> diff = ndiff('one\ntwo\nthree\n'.splitlines(1),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1260 ... 'ore\ntree\nemu\n'.splitlines(1))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1261 >>> print ''.join(diff),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1262 - one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1263 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1264 + ore
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1265 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1266 - two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1267 - three
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1268 ? -
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1269 + tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1270 + emu
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1271 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1272 return Differ(linejunk, charjunk).compare(a, b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1273
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1274 def restore(delta, which):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1275 r"""
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1276 Generate one of the two sequences that generated a delta.
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1277
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1278 Given a `delta` produced by `Differ.compare()` or `ndiff()`, extract
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1279 lines originating from file 1 or 2 (parameter `which`), stripping off line
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1280 prefixes.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1281
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1282 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1283
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1284 >>> diff = ndiff('one\ntwo\nthree\n'.splitlines(1),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1285 ... 'ore\ntree\nemu\n'.splitlines(1))
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1286 >>> diff = list(diff)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1287 >>> print ''.join(restore(diff, 1)),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1288 one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1289 two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1290 three
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1291 >>> print ''.join(restore(diff, 2)),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1292 ore
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1293 tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1294 emu
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1295 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1296 try:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1297 tag = {1: "- ", 2: "+ "}[int(which)]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1298 except KeyError:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1299 raise ValueError, ('unknown delta choice (must be 1 or 2): %r'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1300 % which)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1301 prefixes = (" ", tag)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1302 for line in delta:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1303 if line[:2] in prefixes:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1304 yield line[2:]
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1305
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1306 def _test():
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1307 import doctest, difflib
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1308 return doctest.testmod(difflib)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1309
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1310 if __name__ == "__main__":
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1311 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/difflib.py @ 29384:2d39ec0e55aa legacy-trunk