slice objects vs. []

[Quinn Dunkan]

On Wed, 22 May 2002 15:12:13 -0600, Fernando Pérez <fperez528 at yahoo.com> wrote:
>Quinn Dunkan wrote:
>
>> This seems to imply that [].__getitem__ should accept a slice object.
>> Currently I am writing
>> 
>>     def __getitem__(self, k):
>>         if type(k) is type(slice(0)):
>>             return self.data[k.start:k.end]
>>         else:
>>             return self.data[k]
>> 
>> ... which is awkward, in addition to losing k.step.
>> 
>> BTW, is there any particular reason slice() is not a type?  I expected to be
>> able to write 'isinstance(k, slice)'.
>> 
>
>The docs are a bit outdated, I think. They don't describe __getslice__, which 
>is what you want. Her's an example from my code:

Actually, they do describe __getslice__, with the words "Deprecated since
release 2.0. Support slice objects as parameters to the __getitem__() method."
<wink>

__getslice__ is still supported for backward compatibility though, but

    def __getitem__(self, k): return self.data[k]
    def __getslice__(self, i, j): return self.data[i:j]

... is still somewhat clumsy and still fails if you pass a step.  I would like
to say

    self.__getitem__ = self.data.__getitem__