php Need to move one element at top of array

Question

Have array like this

Array
(
[] => 
[3837920201e05ba7c2fbffd3f1255129] => 'bg img a href Main | Delete etc'
[94ae40ff9b6df5bb123fb12211f48b11] => 'bg img a href Main | Delete etc'
[3974b3863e7ca7b7ea2026e44bbacfd2] => 'bg img a href Main | Delete etc'
)

Want to move key 3974b3863e7ca7b7ea2026e44bbacfd2 at top so array would look like

Array
(
[] => 
[3974b3863e7ca7b7ea2026e44bbacfd2] => 'bg img a href Main | Delete etc'
[3837920201e05ba7c2fbffd3f1255129] => 'bg img a href Main | Delete etc'
[94ae40ff9b6df5bb123fb12211f48b11] => 'bg img a href Main | Delete etc'
)

At first extract item that i want to be at top

$top_image = array_slice( $array, 2, 1 ); 

3974b3863e7ca7b7ea2026e44bbacfd2 is third element (as if key) in array (0,1,2)

Next want to create array $other_images . Decided to remove the initial third element and then merge both arrays.

Trying to remove third element. Read [array_splice][1] understand that first number (offset) is where i want to start to remove and second (length) - how many elements want to remove. So I tried

$top_image = array_splice( $array, 2, 1 ); 

But result is the same as with array_slice.

Then tried

foreach( $arr as $k => $val ){
   if( $k != 2 ){
      $other_images[] = $val;
   }
}

Expect to see 2 remaining elements. But see all 3.

What is wrong? How to remove certain element from array?

Regarding foreach $k can not be equal to 2, because $k is the long string... Tried for , but also not suitable...

Answer 1

If you want to move the last element into the first place use array_pop, array_merge and a foreach trick to keep the key.

foreach($array as $key => $v) {}
$temp = [$key => array_pop($array)];
array_merge($temp, $array);
$array = $temp;

If it's not the last element and you know the key, it's unset that will help you.

// assume $key is set
$temp = [$key => $array[$key]];
unset($array[$key]);
array_merge($temp, $array);
$array = $temp;

Answer 2

Last elem ( 3974b3863e7ca7b7ea2026e44bbacfd2 => 'bg img a href Main | Delete etc' ) to top:

  // last value to top
  $last = array_pop($arr); 
  array_unshift($arr,$last);

Update

  // last couple(key-value) to top
  end($arr);     
  $last_key = key($arr);
  $last_value = array_pop($arr); 
  $arr = array($last_key=>$last_value) + $arr;
  var_dump($arr);