Custom sort multidimensional array using array_multisort()

Question

I have the following array: ``` $array = [ 'note' => [], 'year' => ['2011','2010', '2012'], 'type' => ['conference', 'journal', 'conference'], ]; ``` And I use the following function to sort the array using the field type and another array: ``` function array_multisort_by_order(array $array, $by, array $order) { $order = array_flip($order); $params[] = $array[$by]; foreach($params[0] as &$v) $v = $order[$v]; foreach($array as &$v) $params[] = &$v; unset($v); call_user_func_array('array_multisort', $params); return $array; } ``` When I call the following function I get the following error: ``` $array = array_multisort_by_order($array, 'type', array('conference', 'journal')); print_r($array['type']); ``` Error: ``` Warning: array_multisort(): Array sizes are inconsistent. ``` I know that arrays are inconsistent. Is there a better function to use? Please check: codepad Desired Output: ``` Array ( [note] => Array ( [0] => [1] => [2] => ) [year] => Array ( [0] => 2011 [1] => 2012 [2] => 20…

Accepted Answer

OK, so, one of the first solutions that comes to mind is adding in the empty values to make them consistent:

```
function array_multisort_by_order(array $array, $by, array $order)
{
     $max = max(array_map('count',$array));
    //or, alternatively, depending on input (if there are no 'complete' subarrays):
    //$max = max(array_map(function($arr){return max(array_keys($arr));},$array))+1;

//ADDITION: negative numeric keys:
    $min = min(array_map(function($arr){return min(array_keys($arr));},$array));
    $width = $max - min(0,$min);

foreach($array as &$sub){
        // $addin = array_diff_key(array_fill(0,$max,null),$sub);
        // $addin changed for negative keys:
        $addin = array_diff_key(array_combine(range($min,$max),array_fill(0,$width,null)),$sub);
        $sub = $addin + $sub;
        ksort($sub);
    }
    $order = array_flip($order);
    $params[] = $array[$by];
    foreach($params[0] as &$v) $v = $order[$v];
    foreach($array as &$v) $params[] = &$v; unset($v);
    call_user_func_array('array_multisort', $params);
    //no closeures here:
    //foreach($array as &$sub) $sub = array_filter(function($a){return !is_null($a);},$sub);
    $filter = create_function('$a','return !is_null($a);');
    foreach($array as &$sub) $sub = array_filter($sub,$filter);
    return $array;
}
```

Custom sort multidimensional array using array_multisort()

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