How can I check if a string represents an int, without using try/except?

Question

Is there any way to tell whether a string represents an integer (e.g., \'3\', \'-17\' but not \'3.14\' or \'asf

Answer 1

Use a regular expression:

import re
def RepresentsInt(s):
    return re.match(r"[-+]?\d+$", s) is not None

If you must accept decimal fractions also:

def RepresentsInt(s):
    return re.match(r"[-+]?\d+(\.0*)?$", s) is not None

For improved performance if you're doing this often, compile the regular expression only once using re.compile().