Re: Option for array_column() to preserve keys.

Andreas Hennings wrote on 9/7/21 19:19: > Hello internals, > > The function array_column() would be much more useful if there was an > option to preserve the original array keys. > I can create an RFC, but I think it is better to first discuss the options. > > This is requested in different places on the web, e.g. > > https://stackoverflow.com/questions/27204590/php-array-column-how-to-keep-the-keys/39298759 > > A workaround is proposed here and elsewhere, using array_keys() and > array_combine() to restore the keys. > However, this workaround not only adds complexity, but it breaks down > if some items don't have the value key. See > https://3v4l.org/im2gZ. > > A more robust workaround would be array_map(), but this is more > complex and probably slower than array_column(), for the given > purpose. > > Some links for your convenience: > The function was introduced in this RFC, > https://wiki.php.net/rfc/array_column > It is now documented here, > https://www.php.net/manual/en/function.array-column.php > > Some ideas how this could be fixed: > 1. Allow a magic value (e.g. TRUE) for the $index_key parameter, that > would cause the assoc behavior. To fully avoid BC break, this must be > a value that previously was completely forbidden. The value TRUE is > currently only forbidden with strict_types=1. A value of e.g. new > \stdClass is fully forbidden, but would be weird. A constant could be > introduced, but this would not prevent the BC concern. > 2. Make the function preserve keys if $index_key === NULL. This would > be a full BC break. > 3. Add an additional parameter with a boolean option or with integer > flags. This would be weird, because it would make the $index_key > parameter useless. > 4. Add a new function. > > Personally I would prefer option 1, with value TRUE (I can't think of > something better). > > If I could change history, I would prefer option 2. The current > behavior could still be achieved with array_values(array_column(..)). > > Regards, > Andreas > We originally had a patch for this while PHP 5.5 was still in beta, but we decided against merging it, and I can't remember why. :-) https://github.com/php/php-src/pull/331 Cheers, Ben

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