[Tutor] exceptions problem

[Steven D'Aprano]

On Sat, 11 Sep 2010 09:56:41 am bob gailer wrote:
> > I never thought that you can use a float and a integer to look if
> > the number is a integer.
>
> You can't.

What? Of course you can.

def is_integer(x):
    """Return True if x is an integer."""
    try:
        return 1.0*x == int(x)
    except (TypeError, ValueError):
        return False



And in use:

>>> is_integer("12")
False
>>> is_integer(2.3)
False
>>> is_integer(2.0)
True
>>> is_integer(2)
True


The multiplication by 1.0 is not actually needed, but it doesn't hurt.

[thinks more carefully...] Actually it does hurt:

>>> is_integer(Decimal(2))
False


So although you *can* use float and int to determine if a value is an 
integer, it's best to avoid the float.




-- 
Steven D'Aprano