shuffle

 <?php
 function genArr($len)
 {
     $arr = array();
     $len = $len;
     for ($w=1; $w < $len ; $w++)
     {
         $arr[] = $w;
     }
     return $arr;
 }

 function w_shuffle($arr)
 {
     $end = count($arr)-1;
     for ($w=0; $w < $end ; $w++)
     {
         $rand = rand (0, $end);
         $tmp = $arr[$rand];
         $arr[$rand] = $arr[$w];
         $arr[$w] = $tmp;
     }
     return $arr;
 }

 $arr = genArr(40);
 echo implode(',', $arr).'<br>';
 $res = implode(',', w_shuffle($arr));
 echo $res.'<br>';
 echo implode(',', $arr).'<br>';
 shuffle($arr);
 $res = implode(',',$arr);
 echo $res.'<br>';
 echo implode(',', $arr).'<br>';

 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39
 2,10,23,33,26,28,9,30,21,38,32,31,11,34,8,29,1,39,20,7,4,24,17,35,5,22,14,6,3,16,37,36,25,27,15,12,13,19,18
 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39
 27,39,11,32,2,14,10,15,23,18,38,26,30,29,25,3,24,6,36,20,21,1,5,13,17,28,7,4,8,33,31,16,22,12,35,34,9,37,19
 27,39,11,32,2,14,10,15,23,18,38,26,30,29,25,3,24,6,36,20,21,1,5,13,17,28,7,4,8,33,31,16,22,12,35,34,9,37,19