Simple way to get only non-numeric keys from an array

Question

So I have a PHP array like so:

Array
(
    [0] => Array
        (
            [offset] => 1
            [0] => 1
            [name] => Value:990937970
            [1] => Value:990937970
        )

    [1] => Array
        (
            [offset] => 2
            [0] => 2
            [name] => Value:482758260
            [1] => Value:482758260
        )

    [2] => Array
        (
            [offset] => 3
            [0] => 3
            [name] => Value:2045053536
            [1] => Value:2045053536
        )

)

But I want to change it so that the numeric keys are not returned, like this:

Array
(
    [0] => Array
        (
            [offset] => 1
            [name] => Value:990937970
        )

    [1] => Array
        (
            [offset] => 2
            [name] => Value:482758260
        )

    [2] => Array
        (
            [offset] => 3
            [name] => Value:2045053536
        )

)

My Question: Is there a simple way (without a foreach or while loop) to strip out these numeric keys?

I know that I can just do a foreach where I check if $key is a string; however, loops add to my code's cyclomatic complexity so I am trying to avoid them.

Do these arrays come out of nowhere, or perhaps from a database query? (which could be easier changed to return only associative arrays) — mario
– mario, Commented Oct 26, 2014 at 4:43
They come from a database query, however it would be good to know how to do this on arrays where the exact keys aren't know. (there are a few APIs that return these kinds of arrays too.) — Nicholas Summers
– Nicholas Summers, Commented Oct 26, 2014 at 4:45
See array_intersect/filter answer in duplicate; though might need a second callback for nested lists, and would still be slower than just using *FETCH_ASSOC. — mario
– mario, Commented Oct 26, 2014 at 4:48
@mario I can't get any of those methods working for this array (only effecting top level array) — Nicholas Summers
– Nicholas Summers, Commented Oct 26, 2014 at 4:51

Amal · Accepted Answer · 2014-10-26 04:48:30Z

2

Well, if you really don't want to use a foreach, you can do:

array_walk($data, function (&$v) {
    $keys = array_filter(array_keys($v), function($k) {return !is_int($k);});
    $v = array_intersect_key($v, array_flip($keys));
});

array_walk() still does the looping just as a foreach would; it just isn't explicitly shown.

Also, as mario said, modifying the database query would be a much recommended course of action than this. If you must do this on the PHP side, a foreach would be lot more efficient.

Demo

answered Oct 26, 2014 at 4:48

Amal

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warly · Accepted Answer · 2024-11-19 15:40:47Z

1

It's an old question, but this may be what you are looking for. You filter over the array given the key and remove any which value which key is numeric:

array_filter($input, fn($key) => !is_numeric($key), ARRAY_FILTER_USE_KEY);

answered Nov 19, 2024 at 15:40

warly

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