Intersection of two sets

[Alex]

On Tuesday, 3 December 2019 at 13:43:26 UTC, Jan Hönig wrote:
> It seems i don't google the right keywords.
>
> What i want to do: I have two sets. (I didn't find how to do 
> sets, so i have two associative boolean arrays 
> `bool[<something>]`). And i want to join them, via an 
> intersection.
>
> I know how to code this. Loop over one AA, if the key is also 
> in the other one, we add that to the third array which is going 
> to be returned.
>
> pseudocode:
> alias set = bool[<something>]
> set foo = ...
> set bar = ...
> set result;
>
> foreach(key; foo)
> {
>   if (key in bar)
>   {
>     result[key] = true;
>   }
> }
> return result;
>
>
> 1) Is there a better way for creating a set, other then `alias 
> set = bool[keyClass]`?

This depends on the available accesses on your sets. In terms of 
ranges:
Are your sets InputRanges, ForwardRange, ... ?


> 2) Are there some build-in function for handling such sets?

This is maybe what you are looking for: 
https://dlang.org/phobos/std_algorithm_setops.html