Pythonic way to determine if a string is a number

[python at bdurham.com]

Tim,

> Just for the info, Malcolm, you don't actually need to assign the result of float (input) to anything if you don't need to use it. All you're looking for is the exception. Let the intepreter convert it and then throw it away.

Yes! 

> Also, as an alternative style which can be more appropriate depending on the structure and intention of what you're doing, you can use the else: clause of the try-except block.
>
> try:
>    float (input)
> except ValueError:
>    return False
> else:
>    return True

I follow the semantics, but I don't know why I would prefer the try/else
technique over the simpler:

try:
    float( input )
    return True
except ValueError:
    return False

Thank you for your feedback,

Malcolm