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php字符串截取的代码学习

时间:2021-07-01 10:21:17 帮助过:23人阅读

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

2、UTF-8、GB2312都支持的汉字截取函数

  1. function cut_str($string, $sublen, $start = 0, $code = 'UTF-8')
  2. {
  3. if($code == 'UTF-8')
  4. {
  5. $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";
  6. preg_match_all($pa, $string, $t_string);
  7. if(count($t_string[0])- $start > $sublen)return join('', array_slice($t_string[0], $start, $sublen))."...";
  8. return join('', array_slice($t_string[0], $start, $sublen));
  9. }
  10. else
  11. {
  12. $start = $start*2;
  13. $sublen = $sublen*2;
  14. $strlen = strlen($string);
  15. $tmpstr = '';
  16. for($i=0;$i<$strlen;$i++)
  17. {
  18. if($i>=$start && $i<($start+$sublen))
  19. {
  20. if(ord(substr($string, $i, 1))>129)
  21. {
  22. $tmpstr.= substr($string, $i, 2);
  23. }
  24. else
  25. {
  26. $tmpstr.= substr($string, $i, 1);
  27. }
  28. }
  29. if(ord(substr($string, $i, 1))>129)$i++;
  30. }
  31. if(strlen($tmpstr)<$strlen )$tmpstr.= "...";
  32. return $tmpstr;
  33. }
  34. }
  35. $str = "abcd需要截取的字符串";
  36. echo cut_str($str, 8, 0, 'gb2312');
  37. ?>

3、BugFree 的字符截取函数

  1. function sysSubStr($String,$Length,$Append = false)
  2. {
  3. if (strlen($String)<= $Length )
  4. {
  5. return $String;
  6. }
  7. else
  8. {
  9. $I = 0;
  10. while ($I < $Length)
  11. {
  12. $StringTMP = substr($String,$I,1);
  13. if (ord($StringTMP)>=224 )
  14. {
  15. $StringTMP = substr($String,$I,3);
  16. $I = $I + 3;
  17. }
  18. elseif(ord($StringTMP)>=192 )
  19. {
  20. $StringTMP = substr($String,$I,2);
  21. $I = $I + 2;
  22. }
  23. else
  24. {
  25. $I = $I + 1;
  26. }
  27. $StringLast[]= $StringTMP;
  28. }
  29. $StringLast = implode("",$StringLast);
  30. if($Append)
  31. {
  32. $StringLast .= "...";
  33. }
  34. return $StringLast;
  35. }
  36. }
  37. $String = "CodeBit.cn -- 简单、精彩、通用";
  38. $Length = "18";
  39. $Append = false;
  40. echo sysSubStr($String,$Length,$Append);
  41. ?>

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