PHP 截取字符串专题(转)

1. 截取GB2312中文字符串

 1 <?php
 2  < ?php
 3 //截取中文字符串
 4 function mysubstr($str, $start, $len) {
 5     $tmpstr = "";
 6     $strlen = $start + $len;
 7     for($i = 0; $i < $strlen; $i++) {
 8         if(ord(substr($str, $i, 1)) > 0xa0) {
 9             $tmpstr .= substr($str, $i, 2);
10             $i++;
11         } else
12             $tmpstr .= substr($str, $i, 1);
13     }
14     return $tmpstr;
15 }
16 ?>

2. 截取utf8编码的多字节字符串

 1 <?php
 2 < ?php
 3 //截取utf8字符串
 4 function utf8Substr($str, $from, $len)
 5 {
 6     return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'.
 7                        '((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s',
 8                        '$1',$str);
 9 }
10 ?>

3. UTF-8、GB2312都支持的汉字截取函数

 1 <?php
 2 < ?php
 3 /*
 4 Utf-8、gb2312都支持的汉字截取函数
 5 cut_str(字符串, 截取长度, 开始长度, 编码);
 6 编码默认为 utf-8
 7 开始长度默认为 0
 8 */
 9  
10 function cut_str($string, $sublen, $start = 0, $code = 'UTF-8')
11 {
12     if($code == 'UTF-8')
13     {
14         $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";
15         preg_match_all($pa, $string, $t_string);
16  
17         if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";
18         return join('', array_slice($t_string[0], $start, $sublen));
19     }
20     else
21     {
22         $start = $start*2;
23         $sublen = $sublen*2;
24         $strlen = strlen($string);
25         $tmpstr = '';
26  
27         for($i=0; $i< $strlen; $i++)
28         {
29             if($i>=$start && $i< ($start+$sublen))
30             {
31                 if(ord(substr($string, $i, 1))>129)
32                 {
33                     $tmpstr.= substr($string, $i, 2);
34                 }
35                 else
36                 {
37                     $tmpstr.= substr($string, $i, 1);
38                 }
39             }
40             if(ord(substr($string, $i, 1))>129) $i++;
41         }
42         if(strlen($tmpstr)< $strlen ) $tmpstr.= "...";
43         return $tmpstr;
44     }
45 }
46  
47 $str = "abcd需要截取的字符串";
48 echo cut_str($str, 8, 0, 'gb2312');
49 ?>

4. BugFree 的字符截取函数

 1 <?php
 2 < ?php
 3 /**
 4  * @package     BugFree
 5  * @version     $Id: FunctionsMain.inc.php,v 1.32 2005/09/24 11:38:37 wwccss Exp $
 6  *
 7  *
 8  * Return part of a string(Enhance the function substr())
 9  *
10  * @author                  Chunsheng Wang <wwccss@263.net>
11  * @param string  $String  the string to cut.
12  * @param int     $Length  the length of returned string.
13  * @param booble  $Append  whether append "...": false|true
14  * @return string           the cutted string.
15  */
16 function sysSubStr($String,$Length,$Append = false)
17 {
18     if (strlen($String) < = $Length )
19     {
20         return $String;
21     }
22     else
23     {
24         $I = 0;
25         while ($I < $Length)
26         {
27             $StringTMP = substr($String,$I,1);
28             if ( ord($StringTMP) >=224 )
29             {
30                 $StringTMP = substr($String,$I,3);
31                 $I = $I + 3;
32             }
33             elseif( ord($StringTMP) >=192 )
34             {
35                 $StringTMP = substr($String,$I,2);
36                 $I = $I + 2;
37             }
38             else
39             {
40                 $I = $I + 1;
41             }
42             $StringLast[] = $StringTMP;
43         }
44         $StringLast = implode("",$StringLast);
45         if($Append)
46         {
47             $StringLast .= "...";
48         }
49         return $StringLast;
50     }
51 }
52  
53 $String = "CodeBit.cn -- 简单、精彩、通用";
54 $Length = "18";
55 $Append = false;
56 echo sysSubStr($String,$Length,$Append);
57 ?>

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