Slice objects. How to apply them to strings?

[Jeffery D. Collins]

IIRC, slice objects are intended for use with Numeric arrays.  You might
try using the __getslice__() method for slicing instead.


Dale Strickland-Clark wrote:

> Dale Strickland-Clark <dale at riverhall.NOTHANKS.co.uk> wrote:
> 
> 
>>I'm using Python 2.1 here but this still seems to apply on 2.2
>>
>>I have a little string-based class which needs to emulate strings for
>>most things. This includes slicing.
>>
>>So I need a __getitem__ magic method. 
>>
>>This will get passed a slice object.
>>
>>How am I supposed to translate this into a string slice? 
>>
>>This seems to be the tidiest I can come up with and it's a mess:
>>
>>def __getitem__(self, item):
>>   if item.step:
>>       return self.s[item.start: item.stop: item.step]
>>   if item.start:
>>       return self.s[item.start: item.stop]
>>   return self.s[item.stop]
>>
>>If 'item' is a slice object, shouldn't I just be able to say:
>>
>>   self.s[item]
>>?
>>
>>Wouldn't this be really sensible?
>>
>>What's worse, is that I can't even do this:
>>
>>import operator
>>operator.getitem(self.s, item)
>>
>>Somebody please tell me I'm being dim and I've missed something. How
>>do you apply a slice object to a sequence?
>>
>>Thanks
>>
> 
> Can anyone shed any light on this for me?
> 
> Thanks.
> --
> Dale Strickland-Clark
> Riverhall Systems Ltd
> 



-- 
Jeffery Collins (http://www.boulder.net/~jcollins)