Select n random elements from N without replacement.

random.php

<?php
/**
 * This function will take an array and select n from it
 * without replacement. This can be used as a random number
 * generator
 * 
 * Example: I want to select $n numbers from a pool of $N numbers
 * <code>
 * $values = $srs(range(1,100), 5);
 * </code>
 * The above example will select 5 random numbers 1 to 100 without
 * replacement
 * 
 * Use case, lottery picking numbers, I'm sure there are others.'
 * 
 * @param array $N
 * @param integer $n
 * @return array
 */
$srs = function(array $N, $n) {
  $r = array();
  for ($i = 0; $i < $n; $i++) {
    $x   = floor(count($N)*(hexdec(bin2hex(openssl_random_pseudo_bytes(4)))/0xffffffff));
    $r[] = $N[$x];
    unset($N[$x]);
    $N = array_values($N);
  }
  return $r;
};