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

annotate Lib/difflib.py @ 32527:0da660e05e69 legacy-trunk

"#if WITH_THREAD" is incorrect; must be #ifdef instead; WITH_THREAD isn't always set to an integer value when it's defined.

author	Tim Peters <tim.peters@gmail.com>
date	Wed, 07 Jul 2004 20:42:07 +0000
parents	a46bde9e0c74
children	5546c7ae24f7

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
32339 408a40e65247 Apply heapq.nlargest() to find best matches. Raymond Hettinger <python@rcn.com> parents: 31515 diff changeset	32 import heapq
408a40e65247 Apply heapq.nlargest() to find best matches. Raymond Hettinger <python@rcn.com> parents: 31515 diff changeset	33
29719 fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	34 def _calculate_ratio(matches, length):
fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	35 if length:
fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	36 return 2.0 * matches / length
fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	37 return 1.0
fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	38
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	39 class SequenceMatcher:
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	40
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	41 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	42 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	43 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	44 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	45 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	46 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	47 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	48 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	49 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	50 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	51 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	52
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	53 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	54 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	55 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	56 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	57 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	58 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	59 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	60 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	61 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	62 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	63 "junk" <wink>.
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 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	66
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	67 >>> 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	68 ... "private Thread currentThread;",
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	69 ... "private volatile Thread currentThread;")
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	70 >>>
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 .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	73 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	74 sequences are close matches:
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 >>> 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	77 0.866
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	78 >>>
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	79
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	80 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	81 .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	82
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	83 >>> 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	84 ... 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	85 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	86 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	87 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	88 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	89
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	90 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	91 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	92 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	93
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	94 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	95 use .get_opcodes():
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 >>> 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	98 ... 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	99 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	100 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	101 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	102 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	103
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	104 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	105 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	106 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	107
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	108 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	109 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	110
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	111 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	112 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	113 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	114 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	115
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	116 Methods:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	117
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	118 __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	119 Construct a SequenceMatcher.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	120
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	121 set_seqs(a, b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	122 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	123
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	124 set_seq1(a)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	125 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	126
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	127 set_seq2(b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	128 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	129
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	130 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	131 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	132
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	133 get_matching_blocks()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	134 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	135
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	136 get_opcodes()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	137 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	138
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	139 ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	140 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	141
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	142 quick_ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	143 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	144
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	145 real_quick_ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	146 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	147 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	148
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	149 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	150 """Construct a SequenceMatcher.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	151
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	152 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	153 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	154 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	155 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	156 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	157 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	158 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	159
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	160 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	161 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	162 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	163
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	164 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	165 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	166 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	167 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	168
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	169 # Members:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	170 # a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	171 # first sequence
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	172 # b
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	173 # 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	174 # 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	175 # b2j
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	176 # 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	177 # 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	178 # fullbcount
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	179 # 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	180 # 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	181 # 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	182 # matching_blocks
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	183 # 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	184 # 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	185 # 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	186 # opcodes
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	187 # 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	188 # one of
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	189 # '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	190 # '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	191 # '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	192 # '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	193 # isjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	194 # 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	195 # 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	196 # 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	197 # 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	198 # 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	199 # isbjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	200 # 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	201 # 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	202 # 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	203 # isbpopular
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	204 # 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	205 # (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	206 # 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	207
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	208 self.isjunk = isjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	209 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	210 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	211
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	212 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	213 """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	214
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	215 >>> s = SequenceMatcher()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	216 >>> 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	217 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	218 0.75
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
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	221 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	222 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	223
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	224 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	225 """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	226
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	227 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	228
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	229 >>> 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	230 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	231 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	232 >>> 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	233 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	234 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	235 >>>
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 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	238 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	239 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	240 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	241
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	242 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	243 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	244
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	245 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	246 return
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	247 self.a = a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	248 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	249
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	250 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	251 """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	252
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	253 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	254
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	255 >>> 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	256 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	257 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	258 >>> 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	259 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	260 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	261 >>>
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 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	264 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	265 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	266 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	267
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	268 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	269 """
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 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	272 return
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	273 self.b = b
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	274 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	275 self.fullbcount = None
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	276 self.__chain_b()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	277
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	278 # 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	279 # 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	280 # 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	281 # 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	282 # 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	283 # 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	284 # 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	285 # 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	286 # 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	287 # 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	288 # 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	289 # 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	290 # 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	291 # 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	292 # 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	293 # repeatedly
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	294
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	295 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	296 # 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	297 # 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	298 # 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	299 # 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	300 # 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	301 # have guessed that.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	302 # 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	303 # 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	304 # 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	305 # from the start.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	306 b = self.b
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	307 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	308 self.b2j = b2j = {}
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	309 populardict = {}
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	310 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	311 if elt in b2j:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	312 indices = b2j[elt]
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	313 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	314 populardict[elt] = 1
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	315 del indices[:]
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	316 else:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	317 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	318 else:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	319 b2j[elt] = [i]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	320
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	321 # 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	322 for elt in populardict:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	323 del b2j[elt]
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	324
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	325 # 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	326 # 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	327 # 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	328 # saved.
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	329 isjunk = self.isjunk
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	330 junkdict = {}
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	331 if isjunk:
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	332 for d in populardict, b2j:
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	333 for elt in d.keys():
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	334 if isjunk(elt):
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	335 junkdict[elt] = 1
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	336 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	337
23620 a1de0bab5475 SF 563203. Replaced 'has_key()' with 'in'. Raymond Hettinger <python@rcn.com> parents: 23300 diff changeset	338 # 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	339 # 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	340 # 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	341 # 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	342 # 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	343 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	344 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	345
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	346 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	347 """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	348
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	349 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	350
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	351 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	352 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	353 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	354 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	355 k >= k'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	356 i <= i'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	357 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	358
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	359 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	360 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	361 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	362
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	363 >>> 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	364 >>> 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	365 (0, 4, 5)
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 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	368 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	369 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	370 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	371 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	372 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	373
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	374 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	375 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	376 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	377 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	378
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	379 >>> 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	380 >>> 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	381 (1, 0, 4)
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 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	384
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	385 >>> 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	386 >>> 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	387 (0, 0, 0)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	388 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	389
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	390 # 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	391 # E.g.,
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	392 # ab
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	393 # acab
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	394 # 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	395 # 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	396 # 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	397 # 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	398 # "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	399 # 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	400 # 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	401
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	402 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	403 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	404 # 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	405 # 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	406 # 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	407 j2len = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	408 nothing = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	409 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	410 # 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	411 # 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	412 j2lenget = j2len.get
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	413 newj2len = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	414 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	415 # 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	416 if j < blo:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	417 continue
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	418 if j >= bhi:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	419 break
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	420 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	421 if k > bestsize:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	422 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	423 j2len = newj2len
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	424
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	425 # 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	426 # "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	427 # 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	428 # 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	429 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	430 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	431 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	432 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	433 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	434 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	435 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	436 bestsize += 1
b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	437
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	438 # 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	439 # 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	440 # 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	441 # 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	442 # 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	443 # 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	444 # 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	445 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	446 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	447 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	448 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	449 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	450 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	451 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	452 bestsize = bestsize + 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	453
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	454 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	455
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	456 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	457 """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	458
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	459 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	460 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	461 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	462
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	463 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	464 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	465
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	466 >>> 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	467 >>> 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	468 [(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	469 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	470
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	471 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	472 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	473 self.matching_blocks = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	474 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	475 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	476 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	477 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	478
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	479 # 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	480 # 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	481
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	482 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	483 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	484 # 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	485 # 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	486 # 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	487 if k:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	488 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	489 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	490 answer.append(x)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	491 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	492 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	493
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	494 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	495 """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	496
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	497 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	498 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	499 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	500
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	501 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	502
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	503 '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	504 '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	505 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	506 '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	507 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	508 '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	509
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	510 >>> a = "qabxcd"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	511 >>> b = "abycdf"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	512 >>> 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	513 >>> 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	514 ... 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	515 ... (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	516 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	517 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	518 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	519 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	520 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	521 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	522
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	523 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	524 return self.opcodes
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	525 i = j = 0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	526 self.opcodes = answer = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	527 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	528 # 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	529 # 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	530 # 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	531 # 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	532 # 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	533 tag = ''
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	534 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	535 tag = 'replace'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	536 elif i < ai:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	537 tag = 'delete'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	538 elif j < bj:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	539 tag = 'insert'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	540 if tag:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	541 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	542 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	543 # 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	544 # 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	545 if size:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	546 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	547 return answer
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	548
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	549 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	550 """ 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	551
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	552 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	553 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	554
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	555 >>> from pprint import pprint
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	556 >>> 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	557 >>> b = a[:]
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	558 >>> 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	559 >>> 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	560 >>> 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	561 >>> 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	562 >>> 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	563 [[('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	564 [('equal', 16, 19, 17, 20),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	565 ('replace', 19, 20, 20, 21),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	566 ('equal', 20, 22, 21, 23),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	567 ('delete', 22, 27, 23, 23),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	568 ('equal', 27, 30, 23, 26)],
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	569 [('equal', 31, 34, 27, 30),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	570 ('replace', 34, 35, 30, 31),
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	571 ('equal', 35, 38, 31, 34)]]
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	572 """
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	573
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	574 codes = self.get_opcodes()
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	575 # 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	576 if codes[0][0] == 'equal':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	577 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	578 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	579 if codes[-1][0] == 'equal':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	580 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	581 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	582
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	583 nn = n + n
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 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	586 # 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	587 # 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	588 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	589 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	590 yield group
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	591 group = []
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	592 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	593 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	594 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	595 yield group
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	596
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	597 def ratio(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	598 """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	599
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	600 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	601 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	602 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	603 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	604
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	605 .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	606 .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	607 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	608 upper bound.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	609
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	610 >>> 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	611 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	612 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	613 >>> s.quick_ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	614 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	615 >>> 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	616 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	617 """
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 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	620 self.get_matching_blocks(), 0)
29719 fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	621 return _calculate_ratio(matches, len(self.a) + len(self.b))
16551 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 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	624 """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	625
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	626 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	627 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	628 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	629
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	630 # 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	631 # 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	632 # 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	633 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	634 self.fullbcount = fullbcount = {}
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.b:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	636 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	637 fullbcount = self.fullbcount
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	638 # 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	639 # 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	640 avail = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	641 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	642 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	643 if availhas(elt):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	644 numb = avail[elt]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	645 else:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	646 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	647 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	648 if numb > 0:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	649 matches = matches + 1
29719 fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	650 return _calculate_ratio(matches, len(self.a) + len(self.b))
16551 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 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	653 """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	654
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	655 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	656 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	657 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	658
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	659 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	660 # 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	661 # shorter sequence
29719 fa4cf878c538 Fix SF bug #763023, difflib.py: ratio() zero division not caught Neal Norwitz <nnorwitz@gmail.com> parents: 29517 diff changeset	662 return _calculate_ratio(min(la, lb), la + lb)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	663
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	664 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	665 """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	666
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	667 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	668 string).
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	669
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	670 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	671 (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	672
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	673 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	674 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	675
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	676 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	677 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	678
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	679 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	680 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	681
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	682 >>> 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	683 ['apple', 'ape']
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	684 >>> import keyword as _keyword
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	685 >>> 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	686 ['while']
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	687 >>> 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	688 []
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	689 >>> 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	690 ['except']
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	691 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	692
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	693 if not n > 0:
31515 71a294bd7950 Replace backticks with repr() or "%r" Walter Dörwald <walter@livinglogic.de> parents: 30698 diff changeset	694 raise ValueError("n must be > 0: %r" % (n,))
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	695 if not 0.0 <= cutoff <= 1.0:
31515 71a294bd7950 Replace backticks with repr() or "%r" Walter Dörwald <walter@livinglogic.de> parents: 30698 diff changeset	696 raise ValueError("cutoff must be in [0.0, 1.0]: %r" % (cutoff,))
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	697 result = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	698 s = SequenceMatcher()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	699 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	700 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	701 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	702 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	703 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	704 s.ratio() >= cutoff:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	705 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	706
30698 3e3fd56ce595 Let library modules use the new keyword arguments for list.sort(). Raymond Hettinger <python@rcn.com> parents: 29891 diff changeset	707 # Move the best scorers to head of list
32357 a46bde9e0c74 Reverse argument order for nsmallest() and nlargest(). Raymond Hettinger <python@rcn.com> parents: 32339 diff changeset	708 result = heapq.nlargest(n, result)
30698 3e3fd56ce595 Let library modules use the new keyword arguments for list.sort(). Raymond Hettinger <python@rcn.com> parents: 29891 diff changeset	709 # Strip scores for the best n matches
32339 408a40e65247 Apply heapq.nlargest() to find best matches. Raymond Hettinger <python@rcn.com> parents: 31515 diff changeset	710 return [x for score, x in result]
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	711
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	712 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	713 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	714 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	715
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	716 Example:
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 >>> _count_leading(' abc', ' ')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	719 3
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	720 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	721
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	722 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	723 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	724 i += 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	725 return i
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	726
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	727 class Differ:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	728 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	729 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	730 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	731 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	732 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	733
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	734 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	735
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	736 '- ' 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	737 '+ ' 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	738 ' ' 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	739 '? ' 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	740
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	741 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	742 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	743 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	744
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	745 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	746 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	747 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	748 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	749 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	750
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	751 Example: Comparing two texts.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	752
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	753 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	754 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	755 `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	756
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	757 >>> 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	758 ... 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	759 ... 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	760 ... 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	761 ... '''.splitlines(1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	762 >>> len(text1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	763 4
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	764 >>> text1[0][-1]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	765 '\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	766 >>> 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	767 ... 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	768 ... 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	769 ... 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	770 ... '''.splitlines(1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	771
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	772 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	773
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	774 >>> d = Differ()
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 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	777 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	778
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	779 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	780
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	781 >>> 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	782
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	783 '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	784
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	785 >>> 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	786 >>> _pprint(result)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	787 [' 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	788 '- 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	789 '- 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	790 '+ 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	791 '? ++\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	792 '- 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	793 '? ^ ---- ^\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	794 '+ 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	795 '? ++++ ^ ^\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	796 '+ 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	797
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	798 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	799
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	800 >>> print ''.join(result),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	801 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	802 - 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	803 - 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	804 + 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	805 ? ++
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	806 - 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	807 ? ^ ---- ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	808 + 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	809 ? ++++ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	810 + 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	811
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	812 Methods:
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 __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	815 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	816
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	817 compare(a, b)
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	818 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	819 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	820
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	821 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	822 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	823 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	824
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	825 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	826
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	827 - `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	828 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	829 `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	830 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	831 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	832 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	833 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	834 able to craft.
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	835
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	836 - `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	837 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	838 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	839 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	840 """
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 self.linejunk = linejunk
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	843 self.charjunk = charjunk
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	844
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	845 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	846 r"""
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	847 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	848
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	849 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	850 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	851 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	852 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	853 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	854
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	855 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	856
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	857 >>> 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	858 ... '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	859 - one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	860 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	861 + ore
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 - two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	864 - three
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 + tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	867 + emu
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	868 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	869
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	870 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	871 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	872 if tag == 'replace':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	873 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	874 elif tag == 'delete':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	875 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	876 elif tag == 'insert':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	877 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	878 elif tag == 'equal':
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	879 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	880 else:
31515 71a294bd7950 Replace backticks with repr() or "%r" Walter Dörwald <walter@livinglogic.de> parents: 30698 diff changeset	881 raise ValueError, 'unknown tag %r' % (tag,)
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	882
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	883 for line in g:
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	884 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	885
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	886 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	887 """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	888 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	889 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	890
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	891 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	892 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	893 # 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	894 # 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	895 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	896 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	897 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	898 else:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	899 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	900 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	901
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	902 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	903 for line in g:
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	904 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	905
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	906 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	907 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	908 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	909 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	910 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	911 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	912
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	913 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	914
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	915 >>> d = Differ()
29891 9ca291865f9c Fix faulty doctests. There is no results attribute. Raymond Hettinger <python@rcn.com> parents: 29719 diff changeset	916 >>> results = d._fancy_replace(['abcDefghiJkl\n'], 0, 1,
9ca291865f9c Fix faulty doctests. There is no results attribute. Raymond Hettinger <python@rcn.com> parents: 29719 diff changeset	917 ... ['abcdefGhijkl\n'], 0, 1)
9ca291865f9c Fix faulty doctests. There is no results attribute. Raymond Hettinger <python@rcn.com> parents: 29719 diff changeset	918 >>> print ''.join(results),
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	919 - abcDefghiJkl
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 + abcdefGhijkl
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	922 ? ^ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	923 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	924
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	925 # 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	926 # 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	927 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	928 cruncher = SequenceMatcher(self.charjunk)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	929 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	930
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	931 # 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	932 # (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	933 # 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	934 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	935 bj = b[j]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	936 cruncher.set_seq2(bj)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	937 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	938 ai = a[i]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	939 if ai == bj:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	940 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	941 eqi, eqj = i, j
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	942 continue
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	943 cruncher.set_seq1(ai)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	944 # 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	945 # 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	946 # 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	947 # 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	948 # 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	949 # 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	950 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	951 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	952 cruncher.ratio() > best_ratio:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	953 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	954 if best_ratio < cutoff:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	955 # 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	956 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	957 # 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	958 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	959 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	960 return
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	961 # 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	962 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	963 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	964 # 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	965 eqi = None
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	966
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	967 # 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	968 # identical
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 # 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	971 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	972 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	973
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	974 # 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	975 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	976 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	977 # 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	978 atags = btags = ""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	979 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	980 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	981 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	982 if tag == 'replace':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	983 atags += '^' * la
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 == 'delete':
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 elif tag == 'insert':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	988 btags += '+' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	989 elif tag == 'equal':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	990 atags += ' ' * la
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	991 btags += ' ' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	992 else:
31515 71a294bd7950 Replace backticks with repr() or "%r" Walter Dörwald <walter@livinglogic.de> parents: 30698 diff changeset	993 raise ValueError, 'unknown tag %r' % (tag,)
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	994 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	995 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	996 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	997 # 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	998 yield ' ' + aelt
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 # 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	1001 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	1002 yield line
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1003
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1004 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	1005 g = []
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1006 if alo < ahi:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1007 if 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._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	1009 else:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1010 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	1011 elif blo < bhi:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1012 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	1013
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1014 for line in g:
8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1015 yield line
19200 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 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	1018 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1019 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	1020
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1021 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1022
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1023 >>> d = Differ()
29891 9ca291865f9c Fix faulty doctests. There is no results attribute. Raymond Hettinger <python@rcn.com> parents: 29719 diff changeset	1024 >>> results = d._qformat('\tabcDefghiJkl\n', '\t\tabcdefGhijkl\n',
9ca291865f9c Fix faulty doctests. There is no results attribute. Raymond Hettinger <python@rcn.com> parents: 29719 diff changeset	1025 ... ' ^ ^ ^ ', '+ ^ ^ ^ ')
9ca291865f9c Fix faulty doctests. There is no results attribute. Raymond Hettinger <python@rcn.com> parents: 29719 diff changeset	1026 >>> for line in results: print repr(line)
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1027 ...
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1028 '- \tabcDefghiJkl\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1029 '? \t ^ ^ ^\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1030 '+ \t\tabcdefGhijkl\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1031 '? \t ^ ^ ^\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1032 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1033
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1034 # 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	1035 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	1036 _count_leading(bline, "\t"))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1037 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	1038 atags = atags[common:].rstrip()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1039 btags = btags[common:].rstrip()
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 "- " + aline
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1042 if atags:
20240 5c4261e74478 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 20038 diff changeset	1043 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	1044
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1045 yield "+ " + bline
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1046 if btags:
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1047 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	1048
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1049 # 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	1050 # 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	1051 # before: private Thread currentThread;
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1052 # 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	1053 # 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	1054 # 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	1055 # 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	1056 # 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	1057 # 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	1058 # 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	1059 # 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	1060 # 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	1061 # 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	1062 # 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	1063 # 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	1064 # 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	1065
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1066 import re
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 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	1069 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1070 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	1071
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1072 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1073
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1074 >>> 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	1075 True
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1076 >>> 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	1077 True
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1078 >>> 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	1079 False
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1080 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1081
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1082 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	1083
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1084 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	1085 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1086 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	1087
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1088 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1089
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1090 >>> 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	1091 True
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('\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	1093 True
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1094 >>> 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	1095 False
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1096 >>> 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	1097 False
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1098 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1099
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1100 return ch in ws
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1101
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1102 del re
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1103
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1104
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1105 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	1106 tofiledate='', n=3, lineterm='\n'):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1107 r"""
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1108 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	1109
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1110 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	1111 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	1112 defaults to three.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1113
29517 94ac1d42a420 Fix docstring Raymond Hettinger <python@rcn.com> parents: 29384 diff changeset	1114 By default, the diff control lines (those with ---, +++, or @@) are
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1115 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	1116 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	1117 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	1118 newlines.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1119
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1120 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	1121 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	1122
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1123 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	1124 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	1125 '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	1126 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	1127
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1128 Example:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1129
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1130 >>> 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	1131 ... '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	1132 ... '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	1133 ... lineterm=''):
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1134 ... print line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1135 --- 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	1136 +++ 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	1137 @@ -1,4 +1,4 @@
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1138 +zero
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1139 one
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1140 -two
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1141 -three
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1142 +tree
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1143 four
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1144 """
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1145
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1146 started = False
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1147 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	1148 if not started:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1149 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	1150 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	1151 started = True
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1152 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	1153 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	1154 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	1155 if tag == 'equal':
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 continue
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1159 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	1160 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	1161 yield '-' + line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1162 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	1163 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	1164 yield '+' + line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1165
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1166 # 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	1167 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	1168 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	1169 r"""
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1170 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	1171
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1172 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	1173 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	1174 defaults to three.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1175
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1176 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	1177 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	1178 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	1179 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	1180 newlines.
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1181
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1182 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	1183 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	1184
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1185 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	1186 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	1187 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	1188 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	1189 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	1190
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1191 Example:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1192
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1193 >>> 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	1194 ... '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	1195 ... '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	1196 *** 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	1197 --- 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	1198 ***************
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1199 * 1,4 **
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1200 one
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1201 ! two
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1202 ! three
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1203 four
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1204 --- 1,4 ----
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1205 + zero
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1206 one
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1207 ! tree
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1208 four
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1209 """
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1210
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1211 started = False
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1212 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	1213 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	1214 if not started:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1215 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	1216 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	1217 started = True
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1218
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1219 yield '***************%s' % (lineterm,)
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1220 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	1221 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	1222 else:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1223 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	1224 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	1225 if visiblechanges:
2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1226 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	1227 if tag != 'insert':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1228 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	1229 yield prefixmap[tag] + line
29384 2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1230
29381 15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1231 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	1232 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	1233 else:
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1234 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	1235 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	1236 if visiblechanges:
2d39ec0e55aa For the context and unified diff functions: Raymond Hettinger <python@rcn.com> parents: 29381 diff changeset	1237 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	1238 if tag != 'delete':
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1239 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	1240 yield prefixmap[tag] + line
15f1dc5b7ddc Added functions for creating context diffs and unified diffs. Raymond Hettinger <python@rcn.com> parents: 25953 diff changeset	1241
23300 b5f6e9f6e7f4 Mostly in SequenceMatcher.{__chain_b, find_longest_match}: Tim Peters <tim.peters@gmail.com> parents: 22785 diff changeset	1242 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	1243 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1244 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	1245
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1246 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	1247 functions (or None):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1248
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1249 - 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	1250 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	1251 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	1252 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	1253
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1254 - 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	1255 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	1256 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	1257 in this!).
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 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	1260
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1261 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1262
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1263 >>> 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	1264 ... '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	1265 >>> print ''.join(diff),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1266 - one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1267 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1268 + ore
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1269 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1270 - two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1271 - three
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1272 ? -
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1273 + tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1274 + emu
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1275 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1276 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	1277
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1278 def restore(delta, which):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1279 r"""
20038 8a6f2ee6eaba Make difflib.ndiff() and difflib.Differ.compare() generators. This Tim Peters <tim.peters@gmail.com> parents: 19200 diff changeset	1280 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	1281
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1282 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	1283 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	1284 prefixes.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1285
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1286 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1287
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1288 >>> 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	1289 ... '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	1290 >>> diff = list(diff)
19200 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, 1)),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1292 one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1293 two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1294 three
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1295 >>> 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	1296 ore
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1297 tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1298 emu
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1299 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1300 try:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1301 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	1302 except KeyError:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1303 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	1304 % which)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1305 prefixes = (" ", tag)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1306 for line in delta:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1307 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	1308 yield line[2:]
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1309
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1310 def _test():
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1311 import doctest, difflib
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1312 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	1313
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1314 if __name__ == "__main__":
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1315 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/difflib.py @ 32527:0da660e05e69 legacy-trunk