Insert new item in array on any position in PHP

You may find this a little more intuitive. It only requires one function call to array_splice:

$original = array( 'a', 'b', 'c', 'd', 'e' );$inserted = array( 'x' ); // not necessarily an array, see manual quotearray_splice( $original, 3, 0, $inserted ); // splice in at position 3// $original is now a b c x d e

If replacement is just one element it is not necessary to put array() around it, unless the element is an array itself, an object or NULL.

A function that can insert at both integer and string positions:

/** * @param array      $array * @param int|string $position * @param mixed      $insert */function array_insert(&$array, $position, $insert){    if (is_int($position)) {        array_splice($array, $position, 0, $insert);    } else {        $pos   = array_search($position, array_keys($array));        $array = array_merge(            array_slice($array, 0, $pos),            $insert,            array_slice($array, $pos)        );    }}

Integer usage:

$arr = ["one", "two", "three"];array_insert(    $arr,    1,    "one-half");// ->array (  0 => 'one',  1 => 'one-half',  2 => 'two',  3 => 'three',)

String Usage:

$arr = [    "name"  => [        "type"      => "string",        "maxlength" => "30",    ],    "email" => [        "type"      => "email",        "maxlength" => "150",    ],];array_insert(    $arr,    "email",    [        "phone" => [            "type"   => "string",            "format" => "phone",        ],    ]);// ->array (  'name' =>  array (    'type' => 'string',    'maxlength' => '30',  ),  'phone' =>  array (    'type' => 'string',    'format' => 'phone',  ),  'email' =>  array (    'type' => 'email',    'maxlength' => '150',  ),)

$a = array(1, 2, 3, 4);$b = array_merge(array_slice($a, 0, 2), array(5), array_slice($a, 2));// $b = array(1, 2, 5, 3, 4)