On Tue, May 30, 2023 at 5:35 AM Boro Sitnikovski <buritom...@gmail.com> wrote:
>
> Hello all,
>
> As per the How To Create an RFC instructions, I am sending this e-mail in
> order to get your feedback on my proposal.
>
> I propose introducing a function to PHP core named `array_group`. This
> function takes an array and a function and returns an array that contains
> arrays - groups of consecutive elements. This is very similar to Haskell's
> `groupBy` function.
>
> For some background as to why - usually, when people want to do grouping in
> PHP, they use hash maps, so something like:
>
> ```
> <?php
> $array = [
> [ 'id' => 1, 'value' => 'foo' ],
> [ 'id' => 1, 'value' => 'bar' ],
> [ 'id' => 2, 'value' => 'baz' ],
> ];
>
> $groups = [];
> foreach ( $array as $element ) {
> $groups[ $element['id'] ][] = $element;
> }
>
> var_dump( $groups );
> ```
>
> This can now be achieved as follows (not preserving keys):
>
> ```
> <?php
> $array = [
> [ 'id' => 1, 'value' => 'foo' ],
> [ 'id' => 1, 'value' => 'bar' ],
> [ 'id' => 2, 'value' => 'baz' ],
> ];
>
> $groups = array_group( $array, function( $a, $b ) {
> return $a['id'] == $b['id'];
> } );
> ```
>
> The disadvantage of the first approach is that we are only limited to using
> equality check, and we cannot group by, say, `<` or other functions.
> Similarly, the advantage of the first approach is that the keys are
> preserved, and elements needn't be consecutive.
>
> In any case, I think a utility function such as `array_group` will be widely
> useful.
>
> Please find attached a patch with a proposed implementation. Curious about
> your feedback.
>
> Best,
>
> Boro Sitnikovski
>
I'm sorry if one of the many replies already mentioned this, but there
was a failed RFC for `array_group`:
https://wiki.php.net/rfc/array_column_results_grouping. Note that I
voted against it for technical reasons (the signature was just awful,
we can do better), but I am not against the idea of adding such helper
functions in principle.
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