Boolean tests [was Re: Attack a sacred Python Cow]
Erik Max Francis
max at alcyone.com
Wed Jul 30 08:16:43 CEST 2008
Russ P. wrote:
> On Jul 29, 10:33 pm, Carl Banks <pavlovevide... at gmail.com> wrote:
>> On Jul 30, 1:15 am, "Russ P." <Russ.Paie... at gmail.com> wrote:
>>> Having said that, it would sure be nice to be able to write
>>> if myList is not empty:
>>> instead of
>>> if len(myList) != 0:
>> I can agree with this.
> But I guess that could only work if there were only one empty list
> that represents all empty lists (as there is only one actual "None").
> I don't know if that makes sense or not.
It really doesn't, since it presumably wouldn't apply to just list
types. There are plenty of other sequence types: such as tuples,
strings, or even arbitrary custom types. Emptiness is a test for the
value of an object, not a test for whether it is identical to another
object, so this is a very misleading of the `is` operator, bordering on
This syntax would make far less sense than the existing Boolean test.
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