Question

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How to sort arrays inside an array?
Sort an array by a child array's value in PHP

I’ve got an array that looks like this:

[0] => Array {
    [ID] => 1651,
    [DESCR] => "blabla",
    [SORTNR] => 1,
},
[1] => Array {
    [ID] => 456,
    [DESCR] => "bleble",
    [SORTNR] => 3,
},
[2] => Array {
    [ID] => 158,
    [DESCR] => "bliblablub",
    [SORTNR] => 2,
},

Now I want to sort the subarrays using the value of [SORTNR] descending, so here it should finally look like that:

[1] => Array {
    [ID] => 456,
    [DESCR] => "bleble",
    [SORTNR] => 3,
},
[2] => Array {
    [ID] => 158,
    [DESCR] => "bliblablub",
    [SORTNR] => 2,
},
[0] => Array {
    [ID] => 1651,
    [DESCR] => "blabla",
    [SORTNR] => 1,
},

How can I do that correctly in PHP? I tried some stuff now for four hours and I couldn’t find any good solution….

Thx for help!

Answer 1

function cmp($a, $b) {
  if ($a['SORTNR'] == $b['SORTNR']) {
    return 0;
  }
  return ($a['SORTNR'] < $b['SORTNR']) ? -1 : 1;
}

uasort($arr, 'cmp');

Code adapted from PHP uasort() manual page