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This example compares two strings, considering blanks to be ``junk:''
>>> s = SequenceMatcher(lambda x: x == " ",... "private Thread currentThread;",... "private volatile Thread currentThread;")
ratio() returns a float in [0, 1], measuring the similarityof the sequences. As a rule of thumb, aratio() value over0.6 means the sequences are close matches:
>>> print round(s.ratio(), 3)0.866
If you're only interested in where the sequences match,get_matching_blocks() is handy:
>>> for block in s.get_matching_blocks():... print "a[%d] and b[%d] match for %d elements" % blocka[0] and b[0] match for 8 elementsa[8] and b[17] match for 6 elementsa[14] and b[23] match for 15 elementsa[29] and b[38] match for 0 elements
Note that the last tuple returned byget_matching_blocks() isalways a dummy,(len(a), len(b), 0), and this isthe only case in which the last tuple element (number of elementsmatched) is0.
If you want to know how to change the first sequence into the second,useget_opcodes():
>>> for opcode in s.get_opcodes():... print "%6s a[%d:%d] b[%d:%d]" % opcode equal a[0:8] b[0:8]insert a[8:8] b[8:17] equal a[8:14] b[17:23] equal a[14:29] b[23:38]
See also the functionget_close_matches() in this module,which shows how simple code building onSequenceMatcher can beused to do useful work.
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