收集了php中截取字符串函数_PHP教程

< ?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

//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);

}

?>

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');

?>

/**

* @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) < = $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 = "php100.com-- 简单、精彩、通用";

$Length = "18";

$Append = false;

echo sysSubStr($String,$Length,$Append);

?>