No aa.byKey.length?

[John Colvin via Digitalmars-d-learn]

On Saturday, 2 April 2016 at 16:00:51 UTC, Jonathan M Davis wrote:
> On Saturday, April 02, 2016 15:38:30 Ozan via 
> Digitalmars-d-learn wrote:
>> On Friday, 1 April 2016 at 20:50:32 UTC, Yuxuan Shui wrote:
>> > Why?
>> >
>> > This is annoying when I need to feed it into a function that 
>> > requires hasLength.
>>
>> aa.keys.length
>
> That allocates an array. Doing that would be like doing
> aa.byKeys().array().length. And associate arrays already have 
> length. You
> can do
>
> auto len = aa.length;
>
> The problem is when you want to operate on a range, and the 
> function that you want to pass it to wants length on the range. 
> If byKeys returned a range with length, then that would work, 
> but since it doesn't, it doesn't. Having other ways to get the 
> length doesn't help.
>
> - Jonathan M Davis

Maybe

aa.byKey().takeExactly(aa.length)