Question

I have an array $matrix_part, containing arrays, and I want to rekey the inner keys to start at 1.

I am trying to code below but it doesn’t work – it just stores the new array identically.

$temp_matrix = array();
foreach ($matrix_part as $k => $v){
$temp_matrix[$k++] = $v;
}
$matrix_part = $temp_matrix;

Source array:

Array
(
    [0] => Array
        (
            [0] => 163
            [1] => 23
            [2] => 97
        )
    [1] => Array
        (
            [0] => 163
            [1] => 23
            [2] => 97
        )
    [2] => Array
        (
            [0] => 163
            [1] => 23
            [2] => 97
        )
)

Desired output:

Array
(
    [0] => Array
        (
            [1] => 163
            [2] => 23
            [3] => 97
        )
    [1] => Array
        (
            [1] => 163
            [2] => 23
            [3] => 97
        )
    [2] => Array
        (
            [1] => 163
            [1] => 23
            [3] => 97
        )
)

Answer 1

foreach ($a as $outer_k => $outer_v) {
    for ($i = count($outer_v) - 1; $i >= 0; $i--) {
        $outer_v[$i+1] = $outer_v[$i];
    }
    unset($outer_v[0]);
    $a[$outer_k] = $outer_v;
}

where $a is your input array