Python 3: dict & dict.keys()

[Chris Angelico]

On Thu, Jul 25, 2013 at 3:17 AM, Terry Reedy <tjreedy at udel.edu> wrote:
> On 7/24/2013 12:34 PM, Chris Angelico wrote:
>
>> Side point: Why is iterating over a dict equivalent to .keys() rather
>> than .items()? It feels odd that, with both options viable, the
>> implicit version iterates over half the dict instead of all of it.
>> Obviously it can't be changed now, even if .items() were the better
>> choice, but I'm curious as to the reason for the decision.
>
> This is
> coupled with the fact that the default meaning of 'item in collection' is
> that iterating over 'collection' eventually produces 'item' or a value equal
> to 'item'.

Ahh, that makes sense. I never thought of iteration and 'in' being
connected like that, but yes, that's a solid reason for doing it that
way.

ChrisA