how to check if string is present in python regex code example

Example 1: check if valid regex string python

import re
string = '['
try:
    re.compile(string)
    is_valid = True
except re.error:
    is_valid = False

Example 2: check if string contains python

>>> str = "Messi is the best soccer player"
>>> "soccer" in str
True
>>> "football" in str
False