php - How to know the possible sets of n numbers? -

i have set of numbers s = [1,2,3,4,5,6]; , want make possible pairs among them 1 thing know pair not repeat.

i have used :-

$pairs = array('1','2','3','4','5','6'); $count = count($pairs); $array = array(); for($i = 0;$i <= $count; $i++){     for($j = 1; $j < $count; $j++){         if($i < $j){             $array[$i][] = $pairs[$i].','.$pairs[$j];         }     } } 

i want thing :-

s = [1,2,3,4,5,6];  [1,2],[1,3],[1,4],[1,5],[1,6] [2,3],[2,4],[2,5],[2,6] [3,4],[3,5],[3,6] [4,5],[4,6] [5,6] 

if have better suggestion please reply possible.

build double nested foreach loop on array, build pairs , check if got them.

pseudocode:

pairs = [] foreach(entry in array) {     foreach(entry2 in array) {         pair = [entry, entry2]         if(!alreadyexists(pair in pairs) {             add(pair pairs)         }     } } havefun() 

btw: won't hurt if try yourself, problem rather trivial.