Given array keys that correspond to another array, how can I merge them?

Question

I have the following array that is supposed to only be keys:

$keys = ['mod_4_key'];

and the bigger array which contains a lot of information:

$big_array = [ 'mod_4_key' => ['old' => '', 'info' => ''], 'mod_5_key' => ..]

I would like to, based on what is inside $keys generate a new array with the information from $big_array, as such, if we are to compute the "non-difference" between the arrays, the output should be:

$final_array = [ 'mod_4_key' => ['old' => '', 'info' => '']]

I achieved this using a classic foreach but I was wondering if there was no in-built way to achieve this.

Nigel Ren · Accepted Answer · 2019-11-12 15:47:18Z

4

You may be better off with a simple foreach() loop, but there are probably several ways of achieving this.

This uses array_flip() on the $keys, so that you end up with another associative array, then use array_intersect_key() with the big array first.

$final_array = array_intersect_key($big_array, array_flip($keys));

answered Nov 12, 2019 at 15:47

Nigel Ren

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1 Comment

Daniel Smith Over a year ago

I'll remain with the foreach version, then. It's more terse and avoids me doing two operations.

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