First value as the key in PHP array

Question

I have this array:

$arr = array(
    0 => array( 'id' => 1, 'animal' => 'dog', 'color' => 'red' ),
    1 => array( 'id' => 12, 'animal' => 'cat', 'color' => 'green' ),
    2 => array( 'id' => 37, 'animal' => 'lion', 'color' => 'blue' ),
);

and I want this output:

$arr = array(
    1 => array( 'animal' => 'dog', 'color' => 'red' ),
    12 => array( 'animal' => 'cat', 'color' => 'green' ),
    37 => array( 'animal' => 'lion', 'color' => 'blue' ),
);

Any good idea instead of using php loops, etc ?
Any functions? like array_values or array_combine

=================
Possible solution

$new = array();
foreach( $arr as $item ){
    $id = array_shift( $item );
    $new[$id] = $item;
}

Answer 1

Requires PHP >= 5.5.0 and the id will still be in the nested arrays:

$result = array_column($arr, null, 'id');

Answer 2

One can define a new array and loop through the main array, using array_shift to pop first element (the id field) and then make the remaining part, value for that index in new array:

$new = array();
foreach( $arr as $item ){
    $id = array_shift( $item );
    $new[$id] = $item;
}