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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