PHP按字符串长度分割成数组,支持中文

<?php
 function str_split_unicode($str, $l = 0) {
     if ($l > 0) {
         $ret = array();
         $len = mb_strlen($str, "UTF-8");
         for ($i = 0; $i < $len; $i += $l) {
             $ret[] = mb_substr($str, $i, $l, "UTF-8");
         }
         return $ret;
     }
     return preg_split("//u", $str, -1, PREG_SPLIT_NO_EMPTY);
 }
 ?>
 $s = "还未如愿sss见gfg者不rtret不朽"; // Mild milk
 print_r(str_split($s, 5));
 print_r(str_split_unicode($s, 5));
  
 //输出
 //Array ( [0] => 还&#65533;&#65533; [1] => &#65533;如&#65533; [2] => &#65533;&#65533;sss [3] => 见gf [4] => g者&#65533; [5] => &#65533;&#65533;rtr [6] => et不 [7] => 朽 )
 //Array ( [0] => 还未如愿s [1] => ss见gf [2] => g者不rt [3] => ret不朽 )
http://blog.ppsql.net/post-1843.html