Move an array element to a new index in PHP

Question

I\'m looking for a simple function to move an array element to a new position in the array and resequence the indexes so that there are no gaps in the sequence. It doesnt ne

Answer 1

A lot of good answers. Here's a simple one built on the answer by @RubbelDeCatc. The beauty of it is that you only need to know the array key, not its current position (before repositioning).

/**
 * Reposition an array element by its key.
 *
 * @param array      $array The array being reordered.
 * @param string|int $key They key of the element you want to reposition.
 * @param int        $order The position in the array you want to move the element to. (0 is first)
 *
 * @throws \Exception
 */
function repositionArrayElement(array &$array, $key, int $order): void
{
    if(($a = array_search($key, array_keys($array))) === false){
        throw new \Exception("The {$key} cannot be found in the given array.");
    }
    $p1 = array_splice($array, $a, 1);
    $p2 = array_splice($array, 0, $order);
    $array = array_merge($p2, $p1, $array);
}

Straight forward to use:

$fruits = [
    'bananas'=>'12', 
    'apples'=>'23',
    'tomatoes'=>'21', 
    'nuts'=>'22',
    'foo'=>'a',
    'bar'=>'b'
];

repositionArrayElement($fruits, "foo", 1);

var_export($fruits);

/** Returns
array (
  'bananas' => '12',
  'foo' => 'a', <--  Now moved to position #1
  'apples' => '23',
  'tomatoes' => '21',
  'nuts' => '22',
  'bar' => 'b',
)
**/

Works on numeric arrays also:

$colours = ["green", "blue", "red"];

repositionArrayElement($colours, 2, 0);

var_export($colours);

/** Returns
array (
  0 => 'red', <-- Now moved to position #0
  1 => 'green',
  2 => 'blue',
)
*/

Demo