php中文字符串截取多种方法汇总

<?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;
}
?>

<?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);
}
?>

<?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');
?>

< ?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);
?>