(PHP 4 >= 4.2.0, PHP 5, PHP 7)
array_chunk — Split an array into chunks
$array
   , int $size
   [, bool $preserve_keys = false
  ] )
   Chunks an array into arrays with size elements.
   The last chunk may contain less than size elements.
  
arrayThe array to work on
sizeThe size of each chunk
preserve_keys
       When set to TRUE keys will be preserved.
       Default is FALSE which will reindex the chunk numerically
      
   Returns a multidimensional numerically indexed array, starting with zero,
   with each dimension containing size elements.
  
   If size is less than 1
   E_WARNING will be thrown and NULL returned.
  
Example #1 array_chunk() example
<?php
$input_array = array('a', 'b', 'c', 'd', 'e');
print_r(array_chunk($input_array, 2));
print_r(array_chunk($input_array, 2, true));
?>
The above example will output:
Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )
    [1] => Array
        (
            [0] => c
            [1] => d
        )
    [2] => Array
        (
            [0] => e
        )
)
Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )
    [1] => Array
        (
            [2] => c
            [3] => d
        )
    [2] => Array
        (
            [4] => e
        )
)