Boolean tests [was Re: Attack a sacred Python Cow]

[Steven D'Aprano]

On Thu, 31 Jul 2008 02:41:08 +0000, Steven D'Aprano wrote:

> On Wed, 30 Jul 2008 09:23:05 -0600, Matthew Fitzgibbons wrote:
...
>> Although, if my function is expecting a list, my preference is to do:
>> 
>> if not isinstance(x, list):
>>      raise SomeMeaningfulException()
>> # do stuff with the list
>> 
>> I put my type checking at the top of the function, so readers can
>> reference it easily.
> 
> And thus you break duck-typing and upset anybody who wants to pass a
> sequence that doesn't inherit directly from list.

Correction: delete "directly" from the above.


-- 
Steven