I'm presently trying to create the value of a key in an associative array if it does not exist, and then maintain a reference/pointer to the value. This is what I came up with, but it seems really crufty and I feel that there must be a cleaner way:

Value[string] assocArray;

foreach (...) {
  auto value = key in assocArray;
  if (!value) {
    assocArray[key] = Value();
    value = &assocArray[key];
  }
  value.memberA++;
  value.memberB = "foobar";
}


The goal was to avoid writing:
Value[string] assocArray;

foreach (...) {
  assocArray[key].memberA++;
  assocArray[key].memberB = "foobar";
}

and save a lookup call, but my solution is both less readable and also performs worse for keys not already in the associative array...

On Wednesday, 1 April 2015 at 03:11:58 UTC, Mark Isaacson wrote:
> I'm presently trying to create the value of a key in an associative array if it does not exist, and then maintain a reference/pointer to the value. This is what I came up with, but it seems really crufty and I feel that there must be a cleaner way:
>
> Value[string] assocArray;
>
> foreach (...) {
>   auto value = key in assocArray;
>   if (!value) {
>     assocArray[key] = Value();
>     value = &assocArray[key];
>   }
>   value.memberA++;
>   value.memberB = "foobar";
> }
>
>
> The goal was to avoid writing:
> Value[string] assocArray;
>
> foreach (...) {
>   assocArray[key].memberA++;
>   assocArray[key].memberB = "foobar";
> }
>
> and save a lookup call, but my solution is both less readable and also performs worse for keys not already in the associative array...

You chopped the foreach, can I assume you solition is sooomething like:

   foreach(k, ref value; assocArray) ...

Not quite. You'll note that I am creating the elements in the associative array, not just iterating over them; some of them just happen to be duplicates. FWIW: That foreach happens to be over an input stream.