How to test if object is an integer?

Mon Oct 17 20:33:08 EDT 2011

In article <mailman.2051.1318881724.27778.python-list at python.org>,
 Mathias Lafeldt <mathias.lafeldt at googlemail.com> wrote:
> According to [1], there're more Exceptions to test for:
>> try:
> int(s)
> return True
> except (TypeError, ValueError, OverflowError): # int conversion failed
> return False

I don't think I would catch TypeError here. It kind of depends on how 
isInt() is defined. Is it:
def isInt(s):
 "Return True if s is a string representing an integer"
or is it:
def isInt(s):
 "Return True if s (which must be a string) represents an integer"
If the latter, then passing a non-string violates the contract, and the 
function should raise TypeError. If the former, then you could make 
some argument for catching the TypeError and returning False, but I 
think the second version is what most people have in mind for isInt().
Can you even get an OverflowError any more in a modern Python?
>>>int('99999999999999999999999999999999999999999999999999999999999999999')
99999999999999999999999999999999999999999999999999999999999999999L