PHP 截取字符串函数功能实例

对PHP 截取字符串函数整理感兴趣的小伙伴，下面一起跟随编程之家 jb51.cc的小编两巴掌来看看吧！
1、截取GB2312字符用的函数

<?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,2);
$i++;
} else
$tmpstr .= substr($str,1);
}
return $tmpstr;
}
?>

2. 截取utf8编码的多字节字符串

<?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
/**
 * @param 
 * @author 编程之家 jb51.cc jb51.cc
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],$sublen))."...";
return join('',$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,1))>129)
{
$tmpstr.= substr($string,2);
}
else
{
$tmpstr.= substr($string,1);
}
}
if(ord(substr($string,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,'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 <[e-mail]>
* @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,3);
$I = $I + 3;
}
elseif( ord($StringTMP) >=192 )
{
$StringTMP = substr($String,2);
$I = $I + 2;
}
else
{
$I = $I + 1;
}
$StringLast[] = $StringTMP;
}
$StringLast = implode("",$StringLast);
if($Append)
{
$StringLast .= "...";
}
return $StringLast;
}
}
$String = "jb51.cc-- PHP程序员站";
$Length = "20";
$Append = false;
echo sysSubStr($String,$Append);
?>