Python String to Int Or None

If you want a one-liner like you’ve attempted, go with this:

variable = int(stringToInt) if stringToInt else None

This will assign variable to int(stringToInt) only if is not empty AND is “numeric”. If, for example stringToInt is 'mystring', a ValueError will be raised.

To avoid ValueErrors, so long as you’re not making a generator expression, use a try-except:

try:
    variable = int(stringToInt)
except ValueError:
    variable = None