PHP sort 2d array alphabetically by nested value

Question

I have a PHP array that looks like this:

Array{
    [0] {
        'id'       => '0',
        'title'    => 'foo',
        'address'  => '123 Somewhere',
    }
    [1] {
        'id'       => '1',
        'title'    => 'bar',
        'address'  => '123 Nowhere',
    }
    [2] {
        'id'       => '2',
        'title'    => 'barfoo',
        'address'  => '123 Elsewhere',
    }
    [3] {
        'id'       => '3',
        'title'    => 'foobar',
        'address'  => '123 Whereabouts',
    }
}

and I want to sort it by the 'title' key in the nested arrays, to look like this:

Array{
    [1] {
        'id'       => '1',
        'title'    => 'bar',
        'address'  => '123 Nowhere',
    }
    [2] {
        'id'       => '2',
        'title'    => 'barfoo',
        'address'  => '123 Elsewhere',
    }
    [0] {
        'id'       => '0',
        'title'    => 'foo',
        'address'  => '123 Somewhere',
    }
    [3] {
        'id'       => '3',
        'title'    => 'foobar',
        'address'  => '123 Whereabouts',
    }
}

The first level key values don't matter since I'm keeping track of each nested array via the nested key 'id'.

I've played with ksort() but with no success.

possible duplicate of [PHP sort multidimensional array by value](http://stackoverflow.com/questions/2699086/php-sort-multidimensional-array-by-value) — Evan Mulawski, Mar 26 '12 at 12:44

SirDarius · Accepted Answer · 2012-03-28T18:18:52.867

33

You should use usort() (i'm assuming PHP 5.3+ here):

usort($your_array, function ($elem1, $elem2) {
     return strcmp($elem1['title'], $elem2['title']);
});

Edit: I hadn't noticed you wanted to preserve index association, so you actually need to use uasort() instead, with the same parameters.

Edit2: Here is the pre-PHP 5.3 version:

function compareElems($elem1, $elem2) {
    return strcmp($elem1['title'], $elem2['title']);
}

uasort($your_array, "compareElems");

edited Mar 28 '12 at 18:18

answered Mar 26 '12 at 12:46

SirDarius

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Perfect, that's exactly what I needed. There are a few alternative solutions on SO but this seems more elegant than most (or all) of them. – melat0nin Mar 26 '12 at 13:48
Hmm have just transferred to a server with PHP <5.3, so the embedded function doesn't work.. how would I refactor this to achieve the same effect with the function() outside uasort? – melat0nin Mar 28 '12 at 14:17

PHP sort 2d array alphabetically by nested value

1 Answers1