PHP - how to flip the rows and columns of a 2D array

Question

Normally I\'d be asking how to turn something like this:

1      2        3
4      5        6
7      8        9
10    11       12

Into this:

Answer 1

Modified version of the "accepted" answer, which works MUCH better IMHO:

function array2DFlip($arr) {
 if(!is_array($arr) || count($arr) < 1 || !isset($arr[0])) return array();

 $out = array();

 foreach($arr as $row_id => $row){
    foreach($row as $col_id => $val){
        $out[$col_id][$row_id] = $val;
    }
 }

 return $out;
}