Question

I’ve got some Python code that runs through a list of strings and converts them to integers or floating point numbers if possible. Doing this for integers is pretty easy

if element.isdigit():   newelement = int(element) 

Floating point numbers are more difficult. Right now I’m using partition('.') to split the string and checking to make sure that one or both sides are digits.

partition = element.partition('.') if (partition[0].isdigit() and partition[1] == '.' and partition[2].isdigit())      or (partition[0] == '' and partition[1] == '.' and partition[2].isdigit())      or (partition[0].isdigit() and partition[1] == '.' and partition[2] == ''):   newelement = float(element) 

This works, but obviously the if statement for that is a bit of a bear. The other solution I considered is to just wrap the conversion in a try/catch block and see if it succeeds, as described in this question.

Anyone have any other ideas? Opinions on the relative merits of the partition and try/catch approaches?

Answer 1

I would just use..

try:     float(element) except ValueError:     print "Not a float" 

..it’s simple, and it works. Note that it will still throw OverflowError if element is e.g. 1<<1024.

Another option would be a regular expression:

import re if re.match(r'^-?\d+(?:\.\d+)$', element) is None:     print "Not float"