php字符串截取方法大全php截取字符串四个例子

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

2、截取utf8编码的多字节字符串

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

3、UTF-8、GB2312都支持的汉字截取函数

2. /*
3. 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
4. */
5. function cut_str($string, $sublen, $start = 0, $code = 'UTF-8') {
6. if($code == 'UTF-8') {
7. $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";
8. preg_match_all($pa, $string, $t_string);
9. if(count($t_string[0]) - $start --> $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";
10. return join('', array_slice($t_string[0], $start, $sublen));
11. }
12. else
13. {
14. $start = $start*2;
15. $sublen = $sublen*2;
16. $strlen = strlen($string);
17. $tmpstr = '';
19. for($i=0; $i<$strlen; $i++) { if($i>=$start && $i<($start+$sublen)) { if(ord(substr($string, $i, 1))>129)
20. {
21. $tmpstr.= substr($string, $i, 2);
22. }
23. else
24. {
25. $tmpstr.= substr($string, $i, 1);
26. }
27. }
28. if(ord(substr($string, $i, 1))>129) $i++;
29. }
30. if(strlen($tmpstr)<$strlen ) $tmpstr.= "..."; return $tmpstr; } } $str = "abcd需要截取的字符串"; echo cut_str($str, 8, 0, 'gb2312'); ?>

4、BugFree 的字符截取函数

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