Associative arrays

[Brian Schott via Digitalmars-d-learn]

On Monday, 9 November 2015 at 21:33:09 UTC, TheFlyingFiddle wrote:
> On Monday, 9 November 2015 at 04:52:37 UTC, rsw0x wrote:
>> On Monday, 9 November 2015 at 04:29:30 UTC, Rikki Cattermole 
>> wrote:
>> Fwiw, EMSI provides high quality containers backed by 
>> std.experimental.allocator.
>> https://github.com/economicmodeling/containers
>
> I have a question regarding the implementation of the 
> economicmodeling hashmap. Why must buckets be a power of two? 
> Is it to be able to use the: hash & (buckets.length - 1) for 
> index calculations or is there some other reason?

Yes. It's a hack that gives you a modulus without having to do a 
modulus. It only works on powers of two.