PHP - split array by key -

i've got following array, containing ordered non consecutive numerical keys:

array (     [4] => 2     [5] => 3     [6] => 1     [7] => 2     [8] => 1     [9] => 1     [10] => 1 ) 

i need split array 2 arrays, first array containing keys below 5, , other array consisting of keys 5 , above. please note keys may vary (e.g. 1,3,5,10), therefore cannot use array_slice since don't know offset.

do know simple function accomplish this, without need of using foreach ?

just found out array_slice has preserve_keys parameter.

$a = [     4 => 2,     5 => 3,     6 => 1,     7 => 2,     8 => 1,     9 => 1,     10 => 1 ];  $desired_slice_key = 5; $slice_position = array_search($desired_slice_key, array_keys($a));  $a1 = array_slice($a, 0, $slice_position, true); $a2 = array_slice($a, $slice_position, count($a), true);