python needs leaning stuff from other language

MRAB google at mrabarnett.plus.com
Sat Apr 4 00:55:51 CEST 2009


Tim Wintle wrote:
> On Fri, 2009-04-03 at 13:12 -0400, Mel wrote:
>>>>> I think it would also be better to have One (and prefereably Only One)
>>>>> Obvious Way To Do It. That obvious way, for those who work with
>>>>> Python's ‘set’ and ‘dict’, is a ‘clear’ method. It seems best to have
>>>>> ‘list’ conform with this also.
>>>> Does that mean a one-off special case rule to forbid slices having a
>>>> default?
>>> Why would it do that?
>> Well, if list.clear were truly and strictly to be the only way to clear the 
>> contents of a list, then assigning nothing via the default slice would have 
>> to be ruled out.  `somelist[:] = []` is just a special case of assignment to 
>> a slice generally.
> 
> agreed. If .clear was to be added then really assignments to slices
> should be entirely removed. 
> 
Should we also remove .update from dict?

I see no problem in collections having a .clear method. Saying that "if
c is a collection then c.clear() clears that collection" seems to be a
very duck-typy(?) thing to me.

Assignments to slices is just a feature of ordered collections (well,
lists), and clearing a list by assigning an empty list is just a special
case of that.



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