Index key support for wp_list_pluck(), à la array_column()

[trepmal]

PHP 5.5's ​array_column() has a neat third argument for specifying a field to use as the key for the new array. Patch adds a third optional argument to wp_list_pluck() that mimics that behavior.

Current functionality is this:

wp_list_pluck( get_posts( ), 'post_title' );

which returns an array like

Array
(
    [0] => Hello World!
    [1] => Markup: HTML Tags and Formatting
    [2] => Markup: Image Alignment
    [3] => Markup: Text Alignment
    [4] => Markup: Title With Special Characters ~`!@#$%^&*()-_=+{}[]/;:'"?,.>
)

With the patch, you could specify a field to use as the new keys, so

wp_list_pluck( get_posts( ), 'post_title', 'ID' );

would return

Array
(
    [1699] => Hello World!
    [1178] => Markup: HTML Tags and Formatting
    [1177] => Markup: Image Alignment
    [1176] => Markup: Text Alignment
    [1174] => Markup: Title With Special Characters ~`!@#$%^&*()-_=+{}[]/;:'"?,.>
)

[DrewAPicture]

Neat-o. +1 for this.

[DrewAPicture]

derp. See 28666.diff​.

[nacin]

To optimize the speed of this as much as possible, can we put the if conditional outside of two different foreach loops? We should also reduce the is_object() calls to once per foreach iteration.

We should include in the description for this function that this is an implementation of array_column() that also works with objects.

I wish it only supported all objects or all arrays. As written, it does an is_object() each time. If we somehow knew it was an array of arrays, we could just have this wrap array_column() and get the performance benefits of C.

[trepmal]

updated patch with tests!

[SergeyBiryukov]

Fixed in [28900].