PHP implements double color ball algorithm code

<?php
function DoubleBall(){
  $sysBlueball = mt_rand(1,16);
  $sysRedball = array(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);
  $result = array();
  for($i=0; $i<6; $i++)
  {
    while(true)
    {
      $index = mt_rand(0,32);
      if($sysRedball[$index] != 0){
        $result[$i] = $sysRedball[$index];
        $sysRedball[$index] = 0;
        break;
      }
    }
   }
   $result = implode(&#39;,&#39;,$result);
   echo &#39;你选择的篮球为：&#39;.$sysBlueball.&#39;&#39;;
   echo &#39;你选择的红球为：&#39;.$result.&#39;&#39;;
}
DoubleBall();
?>

你选择的篮球为：3你选择的红球为：29,11,26,14,9,24