Python: Convert a string to an integer

Question

Does anybody have a quickie for converting an unsafe string to an int?

The string typically comes back as: \'234\\r\\n\' or something like

Answer 1

In this case you do have a way to avoid try/except, although I wouldn't recommend it (assuming your input string is named s, and you're in a function that must return something):

xs = s.strip()
if xs[0:1] in '+-': xs = xs[1:]
if xs.isdigit(): return int(s)
else: ...

the ... part in the else is where you return whatever it is you want if, say, s was 'iamnotanumber', '23skidoo', empty, all-spaces, or the like.

Unless a lot of your input strings are non-numbers, try/except is better:

try: return int(s)
except ValueError: ...

you see the gain in conciseness, and in avoiding the fiddly string manipulation and test!-)

I see many answers do int(s.strip()), but that's supererogatory: the stripping's not needed!

>>> int('  23  ')
23

int knows enough to ignore leading and trailing whitespace all by itself!-)