几个好用的截取字符串的php函数分享

<?<span php 
</span><span /*</span><span *
**截取中文字符串 
* edit by www.jbxue.com
*</span><span */</span>
<span function</span> mysubstr(<span $str</span>, <span $start</span>, <span $len</span><span ) { 
</span><span $tmpstr</span> = ""<span ; 
</span><span $strlen</span> = <span $start</span> + <span $len</span><span ; 
</span><span for</span>(<span $i</span> = 0; <span $i</span> < <span $strlen</span>; <span $i</span>++<span ) { 
</span><span if</span>(<span ord</span>(<span substr</span>(<span $str</span>, <span $i</span>, 1)) > 0xa0<span ) { 
</span><span $tmpstr</span> .= <span substr</span>(<span $str</span>, <span $i</span>, 2<span ); 
</span><span $i</span>++<span ; 
} </span><span else</span> 
<span $tmpstr</span> .= <span substr</span>(<span $str</span>, <span $i</span>, 1<span ); 
} 
</span><span return</span> <span $tmpstr</span><span ; 
} 
</span>?>

<?<span php 
</span><span /*</span><span *
* 截取utf8字符串
* edit by www.jbxue.com
</span><span */</span>
<span function</span> utf8Substr(<span $str</span>, <span $from</span>, <span $len</span><span ) 
{ 
</span><span return</span> <span preg_replace</span>('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.<span $from</span>.'}'. 
'((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.<span $len</span>.'}).*#s', 
'$1',<span $str</span><span ); 
} 
</span>?>

<?<span php 
</span><span /*</span><span  
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 
* by www.jbxue.com
</span><span */</span>

<span function</span> cut_str(<span $string</span>, <span $sublen</span>, <span $start</span> = 0, <span $code</span> = 'UTF-8'<span ) 
{ 
</span><span if</span>(<span $code</span> == 'UTF-8'<span ) 
{ 
</span><span $pa</span> = "/[\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]/"<span ; 
</span><span preg_match_all</span>(<span $pa</span>, <span $string</span>, <span $t_string</span><span );

</span><span if</span>(<span count</span>(<span $t_string</span>[0]) - <span $start</span> > <span $sublen</span>) <span return</span> <span join</span>('', <span array_slice</span>(<span $t_string</span>[0], <span $start</span>, <span $sublen</span>))."..."<span ; 
</span><span return</span> <span join</span>('', <span array_slice</span>(<span $t_string</span>[0], <span $start</span>, <span $sublen</span><span )); 
} 
</span><span else</span><span  
{ 
</span><span $start</span> = <span $start</span>*2<span ; 
</span><span $sublen</span> = <span $sublen</span>*2<span ; 
</span><span $strlen</span> = <span strlen</span>(<span $string</span><span ); 
</span><span $tmpstr</span> = ''<span ;

</span><span for</span>(<span $i</span>=0; <span $i</span>< <span $strlen</span>; <span $i</span>++<span ) 
{ 
</span><span if</span>(<span $i</span>>=<span $start</span> && <span $i</span>< (<span $start</span>+<span $sublen</span><span )) 
{ 
</span><span if</span>(<span ord</span>(<span substr</span>(<span $string</span>, <span $i</span>, 1))>129<span ) 
{ 
</span><span $tmpstr</span>.= <span substr</span>(<span $string</span>, <span $i</span>, 2<span ); 
} 
</span><span else</span><span  
{ 
</span><span $tmpstr</span>.= <span substr</span>(<span $string</span>, <span $i</span>, 1<span ); 
} 
} 
</span><span if</span>(<span ord</span>(<span substr</span>(<span $string</span>, <span $i</span>, 1))>129) <span $i</span>++<span ; 
} 
</span><span if</span>(<span strlen</span>(<span $tmpstr</span>)< <span $strlen</span> ) <span $tmpstr</span>.= "..."<span ; 
</span><span return</span> <span $tmpstr</span><span ; 
} 
}

</span><span $str</span> = "abcd需要截取的字符串"<span ; 
</span><span echo</span> cut_str(<span $str</span>, 8, 0, 'gb2312'<span ); 
</span>?>

<?<span php 
</span><span /*</span><span * 
* @package BugFree 
* 
* 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. 
* @by www.jbxue.com
</span><span */</span> 
<span function</span> sysSubStr(<span $String</span>,<span $Length</span>,<span $Append</span> = <span false</span><span ) 
{ 
</span><span if</span> (<span strlen</span>(<span $String</span>) < = <span $Length</span><span  ) 
{ 
</span><span return</span> <span $String</span><span ; 
} 
</span><span else</span><span  
{ 
</span><span $I</span> = 0<span ; 
</span><span while</span> (<span $I</span> < <span $Length</span><span ) 
{ 
</span><span $StringTMP</span> = <span substr</span>(<span $String</span>,<span $I</span>,1<span ); 
</span><span if</span> ( <span ord</span>(<span $StringTMP</span>) >=224<span  ) 
{ 
</span><span $StringTMP</span> = <span substr</span>(<span $String</span>,<span $I</span>,3<span ); 
</span><span $I</span> = <span $I</span> + 3<span ; 
} 
</span><span elseif</span>( <span ord</span>(<span $StringTMP</span>) >=192<span  ) 
{ 
</span><span $StringTMP</span> = <span substr</span>(<span $String</span>,<span $I</span>,2<span ); 
</span><span $I</span> = <span $I</span> + 2<span ; 
} 
</span><span else</span><span  
{ 
</span><span $I</span> = <span $I</span> + 1<span ; 
} 
</span><span $StringLast</span>[] = <span $StringTMP</span><span ; 
} 
</span><span $StringLast</span> = <span implode</span>("",<span $StringLast</span><span ); 
</span><span if</span>(<span $Append</span><span ) 
{ 
</span><span $StringLast</span> .= "..."<span ; 
} 
</span><span return</span> <span $StringLast</span><span ; 
} 
}

</span><span $String</span> = "book.chinaz.com -- 站长书库、站长教程"<span ; 
</span><span $Length</span> = "18"<span ; 
</span><span $Append</span> = <span false</span><span ; 
</span><span echo</span> sysSubStr(<span $String</span>,<span $Length</span>,<span $Append</span><span ); 
</span>?>