Inject an element into an array at a specific position

demos.php

<?php
/* Returns:
array(5) {
  ["red"]=>
  string(3) "Red"
  ["green"]=>
  string(5) "Green"
  ["purple"]=>
  string(6) "Purple"
  ["blue"]=>
  string(4) "Blue"
  ["yellow"]=>
  string(6) "Yellow"
}
*/

$input = array(
    "red"    => "Red",
    "green"  => "Green",
    "blue"   => "Blue",
    "yellow" => "Yellow",
);

cameronjonesweb_inject_into_array( $input, array( 'purple' => 'Purlple' ), 2 );

/* Returns:
array(5) {
  [0]=>
  string(3) "red"
  [1]=>
  string(5) "green"
  [2]=>
  string(4) "blue"
  [3]=>
  string(6) "purple"
  [4]=>
  string(6) "yellow"
}
*/

$input = array("red", "green", "blue", "yellow");

cameronjonesweb_inject_into_array( $input, 'purple', 3 );

inject-into-array.php

<?php
/**
 * Inject element into an array at specific position.
 * Works for both numeric and associative arrays.
 *
 * @param array $array Target array to inject into.
 * @param mixed $to_inject Element to inject.
 * @param int   $position Position to inject into.
 * @return array
 */
function cameronjonesweb_inject_into_array( $array, $to_inject, $position ) {
    $start = array_slice( $array, 0, $position );
    $end   = array_slice( $array, $position );
    if ( ! is_array( $to_inject ) ) {
        $to_inject = array( $to_inject );
    }
    return array_merge( $start, $to_inject, $end );
}