On 4/5/22 11:43 AM, Paul Backus wrote:
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;
}
```
Yeah, or use enumerate. But it's painful:
```d
auto f = arr.enumerate.find!((v, w) => v[1] == w)(which);
auto result = f.front[1];
arr = arr.remove(result[0]);
return result;
```
I have a lib somewhere which isn't complete that allows remembering
indexes for elements so you can tease out the original index, but it
breaks when you use it on strings (of course).
-Steve
