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

Question

with positive integers you could use .isdigit:

>>> '16'.isdigit()
True

it doesn’t work with negative integers though. suppose you could try the following:

>>> s="-17"
>>> s.startswith('-') and s[1:].isdigit()
True

it won’t work with '16.0' format, which is similar to int casting in this sense.

edit:

def check_int(s):
    if s[0] in ('-', '+'):
        return s[1:].isdigit()
    return s.isdigit()