How to rermove non-alphanumeric characters at the beginning or end of a string

Question

I have a list with elements that have unnecessary (non-alphanumeric) characters at the beginning or end of each string.

Ex.

\'cats--\'

Answer 1

def strip_nonalnum(word):
    if not word:
        return word  # nothing to strip
    for start, c in enumerate(word):
        if c.isalnum():
            break
    for end, c in enumerate(word[::-1]):
        if c.isalnum():
            break
    return word[start:len(word) - end]

print([strip_nonalnum(s) for s in thelist])

Or

import re

def strip_nonalnum_re(word):
    return re.sub(r"^\W+|\W+$", "", word)