PHP 截取字符串

11. 截取GB2312中文字符串
2
3< ?php  
4 //截取中文字符串 
5 function mysubstr($str, $start, $len) { 
6     $tmpstr = ""; 
7     $strlen = $start + $len; 
8     for($i = 0; $i < $strlen; $i++) { 
9         if(ord(substr($str, $i, 1)) > 0xa0) { 
10             $tmpstr .= substr($str, $i, 2); 
11             $i++; 
12         } else 
13             $tmpstr .= substr($str, $i, 1); 
14     } 
15     return $tmpstr; 
16 } 
17 ?> 
182. 截取utf8编码的多字节字符串
19
20< ?php 
21 //截取utf8字符串 
22 function utf8Substr($str, $from, $len) 
23 { 
24     return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'. 
25                        '((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s', 
26                        '$1',$str); 
27 } 
28 ?> 
293. UTF-8、GB2312都支持的汉字截取函数
30< ?php 
31 /*  
32 Utf-8、gb2312都支持的汉字截取函数  
33 cut_str(字符串, 截取长度, 开始长度, 编码);  
34 编码默认为 utf-8  
35 开始长度默认为 0  
36 */  
37   
38 function cut_str($string, $sublen, $start = 0, $code = 'UTF-8')  
39 {  
40     if($code == 'UTF-8')  
41     {  
42         $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";  
43         preg_match_all($pa, $string, $t_string);  
44   
45         if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";  
46         return join('', array_slice($t_string[0], $start, $sublen));  
47     }  
48     else  
49     {  
50         $start = $start*2;  
51         $sublen = $sublen*2;  
52         $strlen = strlen($string);  
53         $tmpstr = '';  
54   
55         for($i=0; $i< $strlen; $i++)  
56         {  
57             if($i>=$start && $i< ($start+$sublen))  
58             {  
59                 if(ord(substr($string, $i, 1))>129)  
60                 {  
61                     $tmpstr.= substr($string, $i, 2);  
62                 }  
63                 else  
64                 {  
65                     $tmpstr.= substr($string, $i, 1);  
66                 }  
67             }  
68             if(ord(substr($string, $i, 1))>129) $i++;  
69         }  
70         if(strlen($tmpstr)< $strlen ) $tmpstr.= "...";  
71         return $tmpstr;  
72     }  
73 }  
74   
75 $str = "abcd需要截取的字符串";  
76 echo cut_str($str, 8, 0, 'gb2312');  
77 ?> 
784. BugFree 的字符截取函数
79< ?php  
80 /**  
81  * @package     BugFree  
82  * @version     $Id: FunctionsMain.inc.php,v 1.32 2005/09/24 11:38:37 wwccss Exp $  
83  *  
84  *  
85  * Return part of a string(Enhance the function substr())  
86  *  
87  * @author                   Chunsheng Wang <wwccss@263.net>  
88  * @param string  $String  the string to cut.  
89  * @param int     $Length  the length of returned string.  
90  * @param booble  $Append  whether append "...": false|true  
91  * @return  string           the cutted string.  
92  */  
93 function sysSubStr($String,$Length,$Append = false)  
94 {  
95     if (strlen($String) < = $Length )  
96     {  
97         return $String;  
98     }  
99     else  
100     {  
101         $I = 0;  
102         while ($I < $Length)  
103         {  
104             $StringTMP = substr($String,$I,1);  
105             if ( ord($StringTMP) >=224 )  
106             {  
107                 $StringTMP = substr($String,$I,3);  
108                 $I = $I + 3;  
109             }  
110             elseif( ord($StringTMP) >=192 )  
111             {  
112                 $StringTMP = substr($String,$I,2);  
113                 $I = $I + 2;  
114             }  
115             else  
116             {  
117                 $I = $I + 1;  
118             }  
119             $StringLast[] = $StringTMP;  
120         }  
121         $StringLast = implode("",$StringLast);  
122         if($Append)  
123         {  
124             $StringLast .= "...";  
125         }  
126         return $StringLast;  
127     }  
128 }  
129   
130 $String = "CodeBit.cn -- 简单、精彩、通用";  
131 $Length = "18";  
132 $Append = false;  
133 echo sysSubStr($String,$Length,$Append);  
134 ?>