Pattern search in String using Python

For fun I just thought about writing an algorithm on using pattern search in any given string using python, Lets assume you have a string with a value of “SSDDFFEERRTTYYSS” and a character array [‘D’,’D’], Now use the values of character array as a pattern and search for the maximum character occurrence of match in the string value. in plain words, we have a ..


pattern : [‘D’,’D’] i.e DD

Expected output is :3 (as DD pattern appears thrice [XXDDXXXXXDDDXXX).

Also assume the Char array can be dynamic, I mean could be of any limit of characters.

#@Author :rvashisht

char =[‘D’,’D’]
count = 0

i =0
j = 0
pattern = ”
charLength = len(char) # get the length of char array
for i in range(len(char)):
pattern += char[i]

for j in range(len(string)-1):
#extract the chars from string, it should match char pattern length
chars = string[ j : j+charLength] #search in string with pattern
if pattern == chars : #check if pattern match
print chars, “=”, pattern
count = count +1 # increase the counter

print “Total occurrence of pattern found”, count

Well this is just a try.. Please review and comment..




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