php中文字符串截取多种方法汇总

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);
    ?>

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