if regex in string python 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: Python Regex documentation\

>>> import re
>>> m = re.search('(?<=abc)def', 'abcdef')
>>> m.group(0)
'def'