PHP array combinations

Question

I have an array of 7 numbers (1,2,3,4,5,6,7) and I want to choose 5 of the numbers like
(1,2,3,4,5), (1,2,3,4,6), (1,2,3,4,7).
Note that (1,2,3,4,5) is equal to (4,5,3,1,2), so only one of those should be included in the output.

I would like to know if there is a function in PHP or any algorithm that can do this ? I have no idea where to start from. Can you help me ?

I want all the combinations of 7 given numbers ( they are taken from an array ) put into 5 slots, disregarding order.

Answer 1

You can use the solution found here http://stereofrog.com/blok/on/070910.

Incase the link goes down here's the code....

class Combinations implements Iterator {     protected $c = null;     protected $s = null;     protected $n = 0;     protected $k = 0;     protected $pos = 0;      function __construct($s, $k) {         if(is_array($s)) {             $this->s = array_values($s);             $this->n = count($this->s);         } else {             $this->s = (string) $s;             $this->n = strlen($this->s);         }         $this->k = $k;         $this->rewind();     }     function key() {         return $this->pos;     }     function current() {         $r = array();         for($i = 0; $i < $this->k; $i++)             $r[] = $this->s[$this->c[$i]];         return is_array($this->s) ? $r : implode('', $r);     }     function next() {         if($this->_next())             $this->pos++;         else             $this->pos = -1;     }     function rewind() {         $this->c = range(0, $this->k);         $this->pos = 0;     }     function valid() {         return $this->pos >= 0;     }      protected function _next() {         $i = $this->k - 1;         while ($i >= 0 && $this->c[$i] == $this->n - $this->k + $i)             $i--;         if($i < 0)             return false;         $this->c[$i]++;         while($i++ < $this->k - 1)             $this->c[$i] = $this->c[$i - 1] + 1;         return true;     } }   foreach(new Combinations("1234567", 5) as $substring)     echo $substring, ' '; 

12345 12346 12347 12356 12357 12367 12456 12457 12467 12567 13456 13457 13467 13567 14567 23456 23457 23467 23567 24567 34567