<?php
 $y = '1380';
 $arr = array();
 for($i = 0; $i < 2000; $i ++){
   $arr[] = "{$i}"; //故意用引号包起来设成字符串
 }
 for($i = 0; $i < 2000; $i ++){
   if(!in_array($y, $arr)) continue;
 }
?>

% time   seconds usecs/call   calls   function
------ ----------- ----------- --------- --------------------
95.02  7.417240     368   20146 strtol
2.15  7.160390     413   17316 memcpy
1.63  5.522641     240   22966 free
 0.67  2.275374   2275374     1 curl_global_cleanup
 0.54  2.235466     617   3618 __ctype_tolower_loc
 0.16  2.123547    1194   1778 strrchr
 0.17  1.532224     67   22836 malloc
 0.29  0.382083     67   5678 strlen