longest_common_substring.py

from difflib import SequenceMatcher
 
def longestSubstring(str1,str2):
 
     # initialize SequenceMatcher object with 
     # input string
     seqMatch = SequenceMatcher(None,str1,str2)
 
     # find match of longest sub-string
     # output will be like Match(a=0, b=0, size=5)
     match = seqMatch.find_longest_match(0, len(str1), 0, len(str2))
 
     # print longest substring
     if (match.size!=0):
          print (str1[match.a: match.a + match.size]) 
     else:
          print ('No longest common sub-string found')