1. 截取GB2312中文字符串

<?php    < ?php  //截取中文字符串  function mysubstr($str, $start, $len) {      $tmpstr = "";      $strlen = $start + $len;      for($i = 0; $i < $strlen; $i++) {          if(ord(substr($str, $i, 1)) > 0xa0) {              $tmpstr .= substr($str, $i, 2);              $i++;          } else              $tmpstr .= substr($str, $i, 1);      }      return $tmpstr;  }  ?>  

2. 截取utf8编码的多字节字符串

<?php  < ?php  //截取utf8字符串  function utf8Substr($str, $from, $len)  {      return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'.                         '((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s',                         '$1',$str);  }  ?>  

3. UTF-8、GB2312都支持的汉字截取函数

<?php  < ?php  /*  Utf-8、gb2312都支持的汉字截取函数  cut_str(字符串, 截取长度, 开始长度, 编码);  编码默认为 utf-8  开始长度默认为 0  */    function cut_str($string, $sublen, $start = 0, $code = 'UTF-8')  {      if($code == 'UTF-8')      {          $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";          preg_match_all($pa, $string, $t_string);            if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";          return join('', array_slice($t_string[0], $start, $sublen));      }      else      {          $start = $start*2;          $sublen = $sublen*2;          $strlen = strlen($string);          $tmpstr = '';            for($i=0; $i< $strlen; $i++)          {              if($i>=$start && $i< ($start+$sublen))              {                  if(ord(substr($string, $i, 1))>129)                  {                      $tmpstr.= substr($string, $i, 2);                  }                  else                  {                      $tmpstr.= substr($string, $i, 1);                  }              }              if(ord(substr($string, $i, 1))>129) $i++;          }          if(strlen($tmpstr)< $strlen ) $tmpstr.= "...";          return $tmpstr;      }  }    $str = "abcd需要截取的字符串";  echo cut_str($str, 8, 0, 'gb2312');  ?>    

4. BugFree 的字符截取函数

< ?php  /**   * @package     BugFree   * @version     $Id: FunctionsMain.inc.php,v 1.32 2005/09/24 11:38:37 wwccss Exp $   *   *   * Return part of a string(Enhance the function substr())   *   * @author                  Chunsheng Wang <wwccss@263.net>   * @param string  $String  the string to cut.   * @param int     $Length  the length of returned string.   * @param booble  $Append  whether append "...": false|true   * @return string           the cutted string.   */  function sysSubStr($String,$Length,$Append = false)  {      if (strlen($String) < = $Length )      {          return $String;      }      else      {          $I = 0;          while ($I < $Length)          {              $StringTMP = substr($String,$I,1);              if ( ord($StringTMP) >=224 )              {                  $StringTMP = substr($String,$I,3);                  $I = $I + 3;              }              elseif( ord($StringTMP) >=192 )              {                  $StringTMP = substr($String,$I,2);                  $I = $I + 2;              }              else              {                  $I = $I + 1;              }              $StringLast[] = $StringTMP;          }          $StringLast = implode("",$StringLast);          if($Append)          {              $StringLast .= "...";          }          return $StringLast;      }  }    $String = "17test.info 走在中国自动化测试的前沿";  $Length = "18";  $Append = false;  echo sysSubStr($String,$Length,$Append);  ?>