<?php
  // unordered list
  $arr = array(1, 2, 3, 3.14, 5, 4, 6, 9, 8);

  // searched value
  $x = 3.14;
  $index = count($arr);

  while ($arr[$index--] != $x);

  echo "The value $x found on position " . ($index+1) . "!";
?>