python regex

https://www.tutorialspoint.com/python/python_reg_expressions.htm

Matching Versus Searching

Python offers two different primitive operations based on regular expressions: match checks for a match only at the beginning of the string, while search checks for a match anywhere in the string (this is what Perl does by default).

import re

line = "Cats are smarter than dogs";

matchObj = re.match( r'dogs', line, re.M|re.I)
if matchObj:
   print("match --> matchObj.group() : ", matchObj.group())
else:
   print("No match!!")

searchObj = re.search( r'dogs', line, re.M|re.I)
if searchObj:
   print("search --> searchObj.group() : ", searchObj.group())
else:
   print("Nothing found!!")

console:

No match!!
search --> searchObj.group() :  dogs

Search and Replace

One of the most important re methods that use regular expressions is sub.

re.sub(pattern, repl, string, max=0)