Removing elements from dynamic arrays?

[Paul Backus]

On Tuesday, 5 April 2022 at 14:10:44 UTC, Steven Schveighoffer 
wrote:
> I'd implement it probably like this (for D2):
>
> ```d
> auto drop(T)(ref T[] arr, T which)
> {
>    import std.algorithm, std.range;
>    auto f = arr.find(which);
>    debug if(f.empty) throw ...;
>    auto result = arr.front;
>    arr = arr.remove(&f[0] - &arr[0]); // god I hate this
>    return result;
> }
> ```

I think you can get rid of the ugly pointer arithmetic using 
`countUntil`:

```d
auto drop(T)(ref T[] arr, T which)
{
     import std.algorithm, std.range, std.exception;

     auto i = arr.countUntil(which);
     debug enforce(i < arr.length, "Not found");
     auto result = arr[i];
     arr = arr.remove(i);
     return result;
}
```