swap between php array (move to left ) using splice

array_splice.php

<?php
// take out the target element from array, $key is the target element index number ,  1 means 1 element
$arraySpliced = array_splice($stages, $key, 1); 

// adding the spliced element to the previous index of $key and 0 means extract or slice no element. 
$arraySpliced = array_splice($stages, $key-1, 0, $arraySpliced);

Example

$arraySpliced = array_splice($stages, $key, 1); // take out the target element from array, $key is the target element index number ,  1 means 1 element
// print_r($arraySpliced);
// Array
// (
//     [0] => stdClass Object
//         (
//             [g] => done
//             [l] => Done
//         )

// )
// print_r($stages);
// Array
// (
//     [0] => stdClass Object
//         (
//             [g] => open
//             [l] => Open
//         )

//     [1] => stdClass Object
//         (
//             [g] => in_progress
//             [l] => In Progress
//         )

//     [2] => stdClass Object
//         (
//             [g] => ok
//             [l] => ok
//         )

// )
// adding the spliced element to the previous index of $key and 0 means extract or slice no element. 
$arraySpliced = array_splice($stages, $key-1, 0, $arraySpliced);
print_r($arraySpliced);
// Array
// (
// )
print_r($stages);
// Array
// (
//     [0] => stdClass Object
//         (
//             [g] => open
//             [l] => Open
//         )

//     [1] => stdClass Object
//         (
//             [g] => done
//             [l] => Done
//         )

//     [2] => stdClass Object
//         (
//             [g] => in_progress
//             [l] => In Progress
//         )

//     [3] => stdClass Object
//         (
//             [g] => ok
//             [l] => ok
//         )

// )