php中截取中文字符串

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;
}
?>
</pre>
 2. 截取utf8編碼的多字節字符串 

<?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都支持的漢字截取函數 

<?php
< ?php
/
Utf-8、gb2312都支持的漢字截取函數
cut_str(字符串, 截取長度, 開始長度, 編碼);
編碼默認為 utf-8
開始長度默認為 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');
?>
</pre>
 4. BugFree 的字符截取函數 

< ?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 走在中國自動化測試的前沿";
$Length = "18";
$Append = false;
echo sysSubStr($String,$Length,$Append);
?>
</pre>