#!/usr/bin/env python3
#
# Copyright 2007 Doug Hellmann.
#
"""SequenceMatcher example
"""

#end_pymotw_header
import difflib

s1 = [1, 2, 3, 5, 6, 4]
s2 = [2, 3, 5, 4, 6, 1]

print('Initial data:')
print('s1 =', s1)
print('s2 =', s2)
print('s1 == s2:', s1 == s2)
print()

matcher = difflib.SequenceMatcher(None, s1, s2)
for tag, i1, i2, j1, j2 in reversed(matcher.get_opcodes()):

 if tag == 'delete':
 print('Remove {} from positions [{}:{}]'.format(
 s1[i1:i2], i1, i2))
 print(' before =', s1)
 del s1[i1:i2]

 elif tag == 'equal':
 print('s1[{}:{}] and s2[{}:{}] are the same'.format(
 i1, i2, j1, j2))

 elif tag == 'insert':
 print('Insert {} from s2[{}:{}] into s1 at {}'.format(
 s2[j1:j2], j1, j2, i1))
 print(' before =', s1)
 s1[i1:i2] = s2[j1:j2]

 elif tag == 'replace':
 print(('Replace {} from s1[{}:{}] '
 'with {} from s2[{}:{}]').format(
 s1[i1:i2], i1, i2, s2[j1:j2], j1, j2))
 print(' before =', s1)
 s1[i1:i2] = s2[j1:j2]

 print(' after =', s1, '\n')

print('s1 == s2:', s1 == s2)