Array permutations

[Dukc]

On Saturday, 11 September 2021 at 19:37:42 UTC, Vino wrote:
>    Request your help on the below to print the below array as 
> "Required output", Was able to get these values 
> "[1,2],[2,3],[3,4],[4,5]" by using list.slide(2), need your 
> help to get values "1,3],[1,4],[1,5],[2,4],[2,5],[3,5]"

```d
import std;
auto slideEnds(List)(List list, size_t slideLen)
{	return list.slide(slideLen).map!(window => [window.front, 
window.back]);
}
void main()
{	auto list = [1,2,3,4,5];

     iota(2, list.length)
     .map!(slideLen => list.slideEnds(slideLen))
     .joiner
     .writeln;
}
```

This almost does the trick. It leaves out `[1, 5]` for some 
reason I didn't bother to check though.