What is the best possible way to check if a string can be represented as a number in Python?
The function I currently have right now is:
def is_number(s): try: float(s) return True except ValueError: return False
Which, not only is ugly and slow, seems clunky. However I haven't found a better method because calling
float in the main function is even worse.
Which, not only is ugly and slow
I'd dispute both.
A regex or other string parsing method would be uglier and slower.
I'm not sure that anything much could be faster than the above. It calls the function and returns. Try/Catch doesn't introduce much overhead because the most common exception is caught without an extensive search of stack frames.
The issue is that any numeric conversion function has two kinds of results
C (as an example) hacks around this a number of ways. Python lays it out clearly and explicitly.
I think your code for doing this is perfect.
In case you are looking for parsing (positive, unsigned) integers instead of floats, you can use the
isdigit() function for string objects.
>>> a = "03523" >>> a.isdigit() True >>> b = "963spam" >>> b.isdigit() False
There's also something on Unicode strings, which I'm not too familiar with Unicode - Is decimal/decimal