$array=['a','b','c','d','e','f','g'];
$chunckedArray=array_chunk($array,3);
//output: $chunkedArray=[['a','b','c'],['d','e','f'],['g']]
//Array ( [0] => Array ( [0] => a [1] => b [2] => c ) [1] => Array ( [0] => d [1] => e [2] => f ) [2] => Array ( [0] => g ) )