[Python-ideas] Allow deleting slice in an OrderedDict

[Terry Reedy]

On 12/25/2012 8:56 AM, Ram Rachum wrote:
> When I have an OrderedDict, I want to be able to delete a slice of it. I
> want to be able to do:
>
>      del ordered_dict[:3]
>
> To delete the first 3 items, like I would do in a list.
>
> Is there any reason why this shouldn't be implemented?

An OrderedDict is a mapping (has the mapping api) with a defined 
iteration order (the order of entry). It is not a sequence and does not 
have the sequence api. Indeed, a DictList is not possible because dl[2] 
would look for the item associated with 2 as a key rather than 2 as a 
position. So od[2:3] would *not* be the same as od[2], violating the 
usually properly of within-sequence length-1 slices.

-- 
Terry Jan Reedy