difflib.SequenceMatcher.get_opcodes¶

SequenceMatcher.get_opcodes()[source]¶

Return list of 5-tuples describing how to turn a into b.

Each tuple is of the form (tag, i1, i2, j1, j2). The first tuple has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the tuple preceding it, and likewise for j1 == the previous j2.

The tags are strings, with these meanings:

‘replace’: a[i1:i2] should be replaced by b[j1:j2] ‘delete’: a[i1:i2] should be deleted.

Note that j1==j2 in this case.

‘insert’: b[j1:j2] should be inserted at a[i1:i1].

Note that i1==i2 in this case.

‘equal’: a[i1:i2] == b[j1:j2]

>>> a = "qabxcd"
>>> b = "abycdf"
>>> s = SequenceMatcher(None, a, b)
>>> for tag, i1, i2, j1, j2 in s.get_opcodes():
...    print ("%7s a[%d:%d] (%s) b[%d:%d] (%s)" %
...           (tag, i1, i2, a[i1:i2], j1, j2, b[j1:j2]))
 delete a[0:1] (q) b[0:0] ()
  equal a[1:3] (ab) b[0:2] (ab)
replace a[3:4] (x) b[2:3] (y)
  equal a[4:6] (cd) b[3:5] (cd)
 insert a[6:6] () b[5:6] (f)