Question

How to move all negative elements to the beginning of array in PHP

Answer 1

function move_negative_to_beginning(&$arr) {
    $size = count($arr);
    
    $beginning_index = 0;
    
    for ($i = 0; $i < $size; $i++) {
        if ($arr[$i] < 0) {
            $tmp = $arr[$i];
            $arr[$i] = $arr[$beginning_index];
            $arr[$beginning_index] = $tmp;

            $beginning_index++;
        }
    }
}
        
$arr = array(-1, 8, -6, 21, -3, 4, -2, 7, 15, -30, -40, 9);
        
move_negative_to_beginning($arr);

$size = count($arr);
for ($i = 0; $i < $size; $i++) {
    echo $arr[$i] . " ";
}




/*
run:

-1 -6 -3 -2 -30 -40 21 7 15 8 4 9 

*/

 

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