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

annotate Lib/difflib.py @ 19283:b865cd5c1925 legacy-trunk

Added comments before recently added/assigned slots in the type object, so the backward compatibility issues will be easier to understand. I only added comments indicating additions and assignments back to Python 2.0.

author	Fred Drake <fdrake@acm.org>
date	Wed, 15 Aug 2001 18:32:33 +0000
parents	50fb4683a461
children	8a6f2ee6eaba

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
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	9 Function ndiff(a, b):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	10 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	11
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	12 Function restore(delta, which):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	13 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	14
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	15 Class SequenceMatcher:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	16 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	17
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	18 Class Differ:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	19 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	20 """
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	21
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	22 __all__ = ['get_close_matches', 'ndiff', 'restore', 'SequenceMatcher',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	23 'Differ']
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	24
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	25 TRACE = 0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	26
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	27 class SequenceMatcher:
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	28
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	29 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	30 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	31 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	32 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	33 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	34 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	35 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	36 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	37 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	38 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	39 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	40
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	41 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	42 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	43 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	44 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	45 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	46 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	47 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	48 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	49 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	50 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	51 "junk" <wink>.
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 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	54
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	55 >>> 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	56 ... "private Thread currentThread;",
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	57 ... "private volatile Thread currentThread;")
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	58 >>>
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	59
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	60 .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	61 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	62 sequences are close matches:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	63
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	64 >>> 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	65 0.866
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
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	68 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	69 .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	70
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	71 >>> 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	72 ... 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	73 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	74 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	75 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	76 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	77
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	78 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	79 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	80 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	81
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	82 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	83 use .get_opcodes():
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	84
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	85 >>> 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	86 ... 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	87 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	88 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	89 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	90 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	91
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	92 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	93 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	94 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	95
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	96 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	97 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	98
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	99 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	100 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	101 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	102 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	103
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	104 Methods:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	105
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	106 __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	107 Construct a SequenceMatcher.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	108
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	109 set_seqs(a, b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	110 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	111
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	112 set_seq1(a)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	113 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	114
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	115 set_seq2(b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	116 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	117
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	118 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	119 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	120
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	121 get_matching_blocks()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	122 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	123
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	124 get_opcodes()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	125 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	126
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	127 ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	128 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	129
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	130 quick_ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	131 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	132
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	133 real_quick_ratio()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	134 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	135 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	136
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	137 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	138 """Construct a SequenceMatcher.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	139
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	140 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	141 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	142 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	143 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	144 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	145 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	146 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	147
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	148 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	149 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	150 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	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 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	153 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	154 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	155 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	156
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	157 # Members:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	158 # a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	159 # first sequence
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	160 # b
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	161 # 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	162 # 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	163 # b2j
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	164 # 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	165 # 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	166 # b2jhas
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	167 # b2j.has_key
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	168 # fullbcount
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	169 # for x in b, 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	170 # 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	171 # 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	172 # matching_blocks
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	173 # 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	174 # 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	175 # 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	176 # opcodes
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	177 # 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	178 # one of
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	179 # '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	180 # '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	181 # '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	182 # '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	183 # isjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	184 # 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	185 # 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	186 # 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	187 # 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	188 # 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	189 # isbjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	190 # 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	191 # 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	192 # DOES NOT WORK for x in a!
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	193
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	194 self.isjunk = isjunk
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	195 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	196 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	197
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	198 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	199 """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	200
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	201 >>> s = SequenceMatcher()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	202 >>> 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	203 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	204 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	205 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	206
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	207 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	208 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	209
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	210 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	211 """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	212
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	213 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	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(None, "abcd", "bcde")
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	216 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	217 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	218 >>> 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	219 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	220 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	221 >>>
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	222
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	223 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	224 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	225 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	226 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	227
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	228 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	229 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	230
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	231 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	232 return
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	233 self.a = a
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	234 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	235
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	236 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	237 """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	238
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	239 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	240
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	241 >>> 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	242 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	243 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	244 >>> 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	245 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	246 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	247 >>>
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	248
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	249 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	250 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	251 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	252 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	253
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	254 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	255 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	256
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	257 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	258 return
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	259 self.b = b
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	260 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	261 self.fullbcount = None
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	262 self.__chain_b()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	263
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	264 # 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	265 # 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	266 # 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	267 # 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	268 # 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	269 # 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	270 # also creates the fast isbjunk function ...
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	271 # 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	272 # 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	273 # repeatedly
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	274
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	275 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	276 # 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	277 # 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	278 # 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	279 # 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	280 # 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	281 # have guessed that.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	282 # 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	283 # 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	284 # 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	285 # from the start.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	286 b = self.b
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	287 self.b2j = b2j = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	288 self.b2jhas = b2jhas = b2j.has_key
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	289 for i in xrange(len(b)):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	290 elt = b[i]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	291 if b2jhas(elt):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	292 b2j[elt].append(i)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	293 else:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	294 b2j[elt] = [i]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	295
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	296 # 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	297 # 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	298 # 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	299 # saved.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	300 isjunk, junkdict = self.isjunk, {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	301 if isjunk:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	302 for elt in b2j.keys():
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	303 if isjunk(elt):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	304 junkdict[elt] = 1 # value irrelevant; it's a set
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	305 del b2j[elt]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	306
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	307 # Now for x in b, isjunk(x) == junkdict.has_key(x), but the
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	308 # 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	309 # 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	310 # 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	311 # 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	312 self.isbjunk = junkdict.has_key
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	313
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	314 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	315 """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	316
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	317 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	318
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	319 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	320 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	321 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	322 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	323 k >= k'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	324 i <= i'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	325 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	326
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	327 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	328 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	329 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	330
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	331 >>> 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	332 >>> 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	333 (0, 4, 5)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	334
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	335 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	336 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	337 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	338 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	339 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	340 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	341
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	342 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	343 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	344 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	345 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	346
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	347 >>> 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	348 >>> 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	349 (1, 0, 4)
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 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	352
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	353 >>> 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	354 >>> 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	355 (0, 0, 0)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	356 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	357
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	358 # 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	359 # E.g.,
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	360 # ab
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	361 # acab
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	362 # 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	363 # 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	364 # 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	365 # 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	366 # "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	367 # 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	368 # 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	369
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	370 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	371 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	372 # 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	373 # 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	374 # 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	375 j2len = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	376 nothing = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	377 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	378 # 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	379 # 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	380 j2lenget = j2len.get
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	381 newj2len = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	382 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	383 # 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	384 if j < blo:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	385 continue
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	386 if j >= bhi:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	387 break
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	388 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	389 if k > bestsize:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	390 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	391 j2len = newj2len
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	392
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	393 # 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	394 # 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	395 # 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	396 # 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	397 # 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	398 # 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	399 # 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	400 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	401 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	402 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	403 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	404 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	405 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	406 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	407 bestsize = bestsize + 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	408
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	409 if TRACE:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	410 print "get_matching_blocks", 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	411 print " returns", besti, bestj, bestsize
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	412 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	413
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	414 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	415 """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	416
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	417 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	418 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	419 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	420
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	421 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	422 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	423
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	424 >>> 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	425 >>> 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	426 [(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	427 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	428
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	429 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	430 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	431 self.matching_blocks = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	432 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	433 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	434 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	435 if TRACE:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	436 print '*** matching blocks', self.matching_blocks
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	437 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	438
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	439 # 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	440 # 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	441
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	442 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	443 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	444 # 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	445 # 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	446 # 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	447 if k:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	448 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	449 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	450 answer.append(x)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	451 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	452 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	453
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	454 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	455 """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	456
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	457 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	458 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	459 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	460
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	461 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	462
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	463 '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	464 '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	465 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	466 '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	467 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	468 '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	469
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	470 >>> a = "qabxcd"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	471 >>> b = "abycdf"
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	472 >>> 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	473 >>> 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	474 ... 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	475 ... (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	476 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	477 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	478 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	479 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	480 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	481 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	482
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	483 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	484 return self.opcodes
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	485 i = j = 0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	486 self.opcodes = answer = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	487 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	488 # 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	489 # 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	490 # 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	491 # 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	492 # 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	493 tag = ''
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	494 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	495 tag = 'replace'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	496 elif i < ai:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	497 tag = 'delete'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	498 elif j < bj:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	499 tag = 'insert'
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	500 if tag:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	501 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	502 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	503 # 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	504 # 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	505 if size:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	506 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	507 return answer
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	508
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	509 def ratio(self):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	510 """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	511
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	512 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	513 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	514 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	515 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	516
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	517 .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	518 .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	519 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	520 upper bound.
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 >>> 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	523 >>> s.ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	524 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	525 >>> s.quick_ratio()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	526 0.75
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	527 >>> 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	528 1.0
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	529 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	530
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	531 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	532 self.get_matching_blocks(), 0)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	533 return 2.0 * matches / (len(self.a) + len(self.b))
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	534
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	535 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	536 """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	537
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	538 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	539 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	540 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	541
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	542 # 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	543 # 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	544 # 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	545 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	546 self.fullbcount = fullbcount = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	547 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	548 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	549 fullbcount = self.fullbcount
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	550 # 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	551 # 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	552 avail = {}
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	553 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	554 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	555 if availhas(elt):
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	556 numb = avail[elt]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	557 else:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	558 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	559 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	560 if numb > 0:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	561 matches = matches + 1
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	562 return 2.0 * matches / (len(self.a) + len(self.b))
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	563
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	564 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	565 """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	566
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	567 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	568 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	569 """
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	570
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	571 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	572 # 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	573 # shorter sequence
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	574 return 2.0 * min(la, lb) / (la + lb)
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	575
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	576 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	577 """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	578
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	579 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	580 string).
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	581
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	582 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	583 (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	584
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	585 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	586 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	587
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	588 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	589 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	590
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	591 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	592 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	593
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	594 >>> 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	595 ['apple', 'ape']
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	596 >>> import keyword as _keyword
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	597 >>> 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	598 ['while']
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	599 >>> 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	600 []
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	601 >>> 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	602 ['except']
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	603 """
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 if not n > 0:
16695 e14c5f34fa05 Fix a few small typos in the docstrings. Fred Drake <fdrake@acm.org> parents: 16551 diff changeset	606 raise ValueError("n must be > 0: " + `n`)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	607 if not 0.0 <= cutoff <= 1.0:
16695 e14c5f34fa05 Fix a few small typos in the docstrings. Fred Drake <fdrake@acm.org> parents: 16551 diff changeset	608 raise ValueError("cutoff must be in [0.0, 1.0]: " + `cutoff`)
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	609 result = []
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	610 s = SequenceMatcher()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	611 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	612 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	613 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	614 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	615 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	616 s.ratio() >= cutoff:
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	617 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	618 # Sort by score.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	619 result.sort()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	620 # Retain only the best n.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	621 result = result[-n:]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	622 # Move best-scorer to head of list.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	623 result.reverse()
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	624 # Strip scores.
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	625 return [x for score, x in result]
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	626
19200 50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	627
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	628 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	629 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	630 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	631
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	632 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	633
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	634 >>> _count_leading(' abc', ' ')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	635 3
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	636 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	637
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	638 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	639 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	640 i += 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	641 return i
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	642
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	643 class Differ:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	644 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	645 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	646 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	647 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	648 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	649
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	650 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	651
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	652 '- ' 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	653 '+ ' 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	654 ' ' 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	655 '? ' 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	656
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	657 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	658 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	659 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	660
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	661 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	662 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	663 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	664 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	665 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	666
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	667 Example: Comparing two texts.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	668
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	669 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	670 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	671 `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	672
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	673 >>> 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	674 ... 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	675 ... 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	676 ... 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	677 ... '''.splitlines(1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	678 >>> len(text1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	679 4
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	680 >>> text1[0][-1]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	681 '\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	682 >>> 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	683 ... 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	684 ... 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	685 ... 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	686 ... '''.splitlines(1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	687
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	688 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	689
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	690 >>> d = Differ()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	691
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	692 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	693 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	694
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	695 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	696
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	697 >>> result = d.compare(text1, text2)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	698
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	699 '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	700
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	701 >>> 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	702 >>> _pprint(result)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	703 [' 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	704 '- 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	705 '- 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	706 '+ 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	707 '? ++\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	708 '- 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	709 '? ^ ---- ^\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	710 '+ 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	711 '? ++++ ^ ^\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	712 '+ 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	713
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	714 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	715
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	716 >>> print ''.join(result),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	717 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	718 - 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	719 - 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	720 + 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	721 ? ++
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	722 - 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	723 ? ^ ---- ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	724 + 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	725 ? ++++ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	726 + 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	727
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	728 Methods:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	729
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	730 __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	731 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	732
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	733 compare(a, b)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	734 Compare two sequences of lines; return the resulting delta (list).
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
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	737 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	738 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	739 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	740
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	741 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	742
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	743 - `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	744 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	745 `IS_LINE_JUNK` may be used to filter out lines without visible
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	746 characters, except for at most one splat ('#').
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	747
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	748 - `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	749 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	750 whitespace characters (a blank or tab; note: bad idea to include
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	751 newline in this!).
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
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	754 self.linejunk = linejunk
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	755 self.charjunk = charjunk
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	756 self.results = []
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	757
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	758 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	759 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	760 Compare two sequences of lines; return the resulting delta (list).
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	761
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	762 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	763 newlines. Such sequences can be obtained from the `readlines()` method
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	764 of file-like objects. The list returned is also made up of
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	765 newline-terminated strings, ready to be used with the `writelines()`
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	766 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	767
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	768 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	769
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	770 >>> 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	771 ... '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	772 - one
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 + ore
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 - two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	777 - three
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 + tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	780 + emu
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	781 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	782
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	783 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	784 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	785 if tag == 'replace':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	786 self._fancy_replace(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	787 elif tag == 'delete':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	788 self._dump('-', a, alo, ahi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	789 elif tag == 'insert':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	790 self._dump('+', b, blo, bhi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	791 elif tag == 'equal':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	792 self._dump(' ', a, alo, ahi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	793 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	794 raise ValueError, 'unknown tag ' + `tag`
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	795 results = self.results
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	796 self.results = []
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	797 return results
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	798
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	799 def _dump(self, tag, x, lo, hi):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	800 """Store comparison results for a same-tagged range."""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	801 for i in xrange(lo, hi):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	802 self.results.append('%s %s' % (tag, x[i]))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	803
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	804 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	805 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	806 # 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	807 # 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	808 if bhi - blo < ahi - alo:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	809 self._dump('+', b, blo, bhi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	810 self._dump('-', a, alo, ahi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	811 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	812 self._dump('-', a, alo, ahi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	813 self._dump('+', b, blo, bhi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	814
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	815 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	816 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	817 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	818 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	819 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	820 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	821
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	822 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	823
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	824 >>> d = Differ()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	825 >>> d._fancy_replace(['abcDefghiJkl\n'], 0, 1, ['abcdefGhijkl\n'], 0, 1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	826 >>> print ''.join(d.results),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	827 - abcDefghiJkl
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	828 ? ^ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	829 + abcdefGhijkl
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	830 ? ^ ^ ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	831 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	832
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	833 if TRACE:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	834 self.results.append('*** _fancy_replace %s %s %s %s\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	835 % (alo, ahi, blo, bhi))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	836 self._dump('>', a, alo, ahi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	837 self._dump('<', b, blo, bhi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	838
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	839 # 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	840 # 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	841 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	842 cruncher = SequenceMatcher(self.charjunk)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	843 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	844
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	845 # 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	846 # (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	847 # 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	848 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	849 bj = b[j]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	850 cruncher.set_seq2(bj)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	851 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	852 ai = a[i]
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	853 if ai == bj:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	854 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	855 eqi, eqj = i, j
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	856 continue
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	857 cruncher.set_seq1(ai)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	858 # 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	859 # 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	860 # 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	861 # 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	862 # 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	863 # 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	864 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	865 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	866 cruncher.ratio() > best_ratio:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	867 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	868 if best_ratio < cutoff:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	869 # 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	870 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	871 # no identical pair either -- treat it as a straight replace
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	872 self._plain_replace(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	873 return
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	874 # 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	875 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	876 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	877 # 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	878 eqi = None
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	879
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	880 # 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	881 # identical
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	882 if TRACE:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	883 self.results.append('*** best_ratio %s %s %s %s\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	884 % (best_ratio, best_i, best_j))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	885 self._dump('>', a, best_i, best_i+1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	886 self._dump('<', b, best_j, best_j+1)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	887
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	888 # pump out diffs from before the synch point
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	889 self._fancy_helper(a, alo, best_i, b, blo, best_j)
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 # 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	892 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	893 if eqi is None:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	894 # 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	895 atags = btags = ""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	896 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	897 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	898 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	899 if tag == 'replace':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	900 atags += '^' * la
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	901 btags += '^' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	902 elif tag == 'delete':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	903 atags += '-' * la
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	904 elif tag == 'insert':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	905 btags += '+' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	906 elif tag == 'equal':
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	907 atags += ' ' * la
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	908 btags += ' ' * lb
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	909 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	910 raise ValueError, 'unknown tag ' + `tag`
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	911 self._qformat(aelt, belt, atags, btags)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	912 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	913 # the synch pair is identical
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	914 self.results.append(' ' + aelt)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	915
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	916 # pump out diffs from after the synch point
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	917 self._fancy_helper(a, best_i+1, ahi, b, best_j+1, bhi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	918
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	919 def _fancy_helper(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	920 if alo < ahi:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	921 if blo < bhi:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	922 self._fancy_replace(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	923 else:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	924 self._dump('-', a, alo, ahi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	925 elif blo < bhi:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	926 self._dump('+', b, blo, bhi)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	927
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	928 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	929 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	930 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	931
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	932 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	933
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	934 >>> d = Differ()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	935 >>> d._qformat('\tabcDefghiJkl\n', '\t\tabcdefGhijkl\n',
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	936 ... ' ^ ^ ^ ', '+ ^ ^ ^ ')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	937 >>> for line in d.results: print repr(line)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	938 ...
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	939 '- \tabcDefghiJkl\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	940 '? \t ^ ^ ^\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	941 '+ \t\tabcdefGhijkl\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	942 '? \t ^ ^ ^\n'
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	943 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	944
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	945 # 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	946 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	947 _count_leading(bline, "\t"))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	948 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	949 atags = atags[common:].rstrip()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	950 btags = btags[common:].rstrip()
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	951
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	952 self.results.append("- " + aline)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	953 if atags:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	954 self.results.append("? %s%s\n" % ("\t" * common, atags))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	955
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	956 self.results.append("+ " + bline)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	957 if btags:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	958 self.results.append("? %s%s\n" % ("\t" * common, btags))
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	959
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	960 # 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	961 # 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	962 # before: private Thread currentThread;
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	963 # 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	964 # 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	965 # 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	966 # 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	967 # 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	968 # 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	969 # 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	970 # 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	971 # 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	972 # 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	973 # 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	974 # 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	975 # 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	976
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	977 import re
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	978
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	979 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	980 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	981 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	982
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	983 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	984
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	985 >>> IS_LINE_JUNK('\n')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	986 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	987 >>> IS_LINE_JUNK(' # \n')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	988 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	989 >>> IS_LINE_JUNK('hello\n')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	990 0
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	991 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	992
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	993 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	994
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	995 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	996 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	997 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	998
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	999 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1000
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1001 >>> IS_CHARACTER_JUNK(' ')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1002 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1003 >>> IS_CHARACTER_JUNK('\t')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1004 1
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1005 >>> IS_CHARACTER_JUNK('\n')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1006 0
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1007 >>> IS_CHARACTER_JUNK('x')
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1008 0
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1009 """
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1010
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1011 return ch in ws
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1012
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1013 del re
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1014
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1015 def ndiff(a, b, linejunk=IS_LINE_JUNK, charjunk=IS_CHARACTER_JUNK):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1016 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1017 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	1018
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1019 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	1020 functions (or None):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1021
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1022 - linejunk: A function that should accept a single string argument, and
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1023 return true iff the string is junk. The default is module-level function
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1024 IS_LINE_JUNK, which filters out lines without visible characters, except
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1025 for at most one splat ('#').
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1026
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1027 - 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	1028 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	1029 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	1030 in this!).
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1031
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1032 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	1033
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1034 Example:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1035
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1036 >>> 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	1037 ... '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	1038 >>> print ''.join(diff),
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1039 - one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1040 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1041 + ore
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1042 ? ^
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1043 - two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1044 - three
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1045 ? -
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1046 + tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1047 + emu
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 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	1050
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1051 def restore(delta, which):
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1052 r"""
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1053 Return one of the two sequences that generated a delta.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1054
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1055 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	1056 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	1057 prefixes.
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1058
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1059 Examples:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1060
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1061 >>> 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	1062 ... '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	1063 >>> 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	1064 one
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1065 two
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1066 three
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1067 >>> 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	1068 ore
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1069 tree
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1070 emu
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 try:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1073 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	1074 except KeyError:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1075 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	1076 % which)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1077 prefixes = (" ", tag)
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1078 results = []
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1079 for line in delta:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1080 if line[:2] in prefixes:
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1081 results.append(line[2:])
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1082 return results
50fb4683a461 SF patch #445412 extract ndiff functionality to difflib, from Tim Peters <tim.peters@gmail.com> parents: 16703 diff changeset	1083
16551 7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1084 def _test():
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1085 import doctest, difflib
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1086 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	1087
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1088 if __name__ == "__main__":
7de5043827f7 Moved SequenceMatcher from ndiff into new std library module difflib.py. Tim Peters <tim.peters@gmail.com> parents: diff changeset	1089 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/difflib.py @ 19283:b865cd5c1925 legacy-trunk