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php字符串截取问题_php技巧

May 17, 2016 am 09:43 AM
String interception

但是在英文和汉字混合的情况下会出现如下问题:

如果有这样一个字符串
$str="这是一个字符串";
为了截取该串的前10个字符,使用
if(strlen($str)>10) $str=substr($str,10)."…";
那么,echo $str的输出应该是"这是一个字…"

假设
$str="这是1个字符串";
这个串中包含了一个半角字符,同样执行:
if(strlen($str)>10) $str=substr($str,10);
由于原字符串$str的第10、11个字符构成了汉字“符”;
执行串分割后会将该汉字一分为二,这样被截取的串就会发现乱码现象。


请问这种问题如何解决?即要使过长字符串实现分割,又不能让它发生乱码?

复制代码 代码如下:

//村里有很多,这个是gb2312
function substrs($content,$length='30')
{
    if($length && strlen($content)>$length)
    {
        $num=0;
        for($i=0;$i        {
            if(ord($content[$i])>127)
            {
                $num++;
            }
        }
        $num%2==1 ? $content=substr($content,0,$length-4):$content=substr($content,0,$length-3);
    }
    return $content;
}
?>
 
复制代码 代码如下:

function cutstr($string, $length, $dot = ' ...') {
        $strcut = '';
        for($i = 0; $i                 $strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
        }
        return $strcut.$dot;
}

复制代码 代码如下:

function cutTitle($str, $len, $tail = ""){
        $length                = strlen($str);
        $lentail        = strlen($tail);
        $result                = "";
        if($length > $len){
        $len = $len - $lentail;
                for($i = 0;$i                         if(ord($str[$i])                                 $result .= $str[$i];
                        }else{
                                $result .= $str[$i];
                                ++ $i;
                                $result .= $str[$i];
                        }
                }
                $result = strlen($result) > $len ? substr($result, 0, -2) . $tail : $result . $tail;
        }else{
                $result = $str;
        }
        return $result;
}

以下是一些补充:
1. 截取GB2312中文字符串
代码如下:
复制代码 代码如下:

//截取中文字符串
function mysubstr($str, $start, $len) {
$tmpstr = "";
$strlen = $start + $len;
for($i = 0; $i if(ord(substr($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
代码如下:
复制代码 代码如下:

//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
代码如下:
复制代码 代码如下:

/*
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; $i{
if($i>=$start && $i{
if(ord(substr($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)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
代码如下:
复制代码 代码如下:

/**
* @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
* @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) {
return $String;
}
else
{
$I = 0;
while ($I {
$StringTMP = substr($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 = "www.baidu.com";
$Length = "18";
$Append = false;
echo sysSubStr($String,$Length,$Append);
?>
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