How to Sort a Multi-dimensional Array by Value

Question

How can I sort this array by the value of the "order" key?

Even though the values are currently sequential, they will not always be.

Array (     [0] => Array         (             [hashtag] => a7e87329b5eab8578f4f1098a152d6f4             [title] => Flower             [order] => 3         )      [1] => Array         (             [hashtag] => b24ce0cd392a5b0b8dedc66c25213594             [title] => Free             [order] => 2         )      [2] => Array         (             [hashtag] => e7d31fc0602fb2ede144d18cdffd816b             [title] => Ready             [order] => 1         ) ) 

Answer 1

Try a usort. If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

function sortByOrder($a, $b) {     return $a['order'] - $b['order']; }  usort($myArray, 'sortByOrder'); 

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {     return $a['order'] - $b['order']; }); 

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {     return $a['order'] <=> $b['order']; }); 

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {     $retval = $a['order'] <=> $b['order'];     if ($retval == 0) {         $retval = $a['suborder'] <=> $b['suborder'];         if ($retval == 0) {             $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];         }     }     return $retval; }); 

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual.

Answer 2

function aasort (&$array, $key) {     $sorter = array();     $ret = array();     reset($array);     foreach ($array as $ii => $va) {         $sorter[$ii] = $va[$key];     }     asort($sorter);     foreach ($sorter as $ii => $va) {         $ret[$ii] = $array[$ii];     }     $array = $ret; }  aasort($your_array, "order");