Judge the Regular Expression of Chinese and Japanese Korean

Encoding of GBK and UTF8 in PHP

I. Encoding range

1. GBK (GB2312/GB18030)
\ X00-\ xffGBK dubyte encoding range
\ X20-\ x7fASCII
\ Xa1-\ xffChinese
\ X80-\ xffChinese

2. UTF-8 (Unicode)
\ U4e00-\ u9fa5 (Chinese)
\ X3130-\ x318F (Korean
\ XAC00-\ xD7A3 (Korean)
\ U0800-\ u4e00 (Japanese)
Ps: Korean is a character greater than [\ u9fa5]

Regular Expression example:
Preg_replace ("/([\ x80-\ xff])/", "", $ str );
Preg_replace ("/([u4e00-u9fa5])/", "", $ str );

Ii. code example

// Determine whether the content contains Chinese characters-GBK (PHP)
Function check_is_chinese ($ s ){
   Return preg_match ('/[\ x80-\ xff]./', $ s );
}

// Obtain the string length-GBK (PHP)
Function gb_strlen ($ str ){
   $ Count = 0;
   For ($ I = 0; $ I <strlen ($ str); $ I ++ ){
       $ S = substr ($ str, $ I, 1 );
       If (preg_match ("/[\ x80-\ xff]/", $ s) ++ $ I;
       + + $ Count;
   }
   Return $ count;
}

// Truncate the string-GBK (PHP)
Function gb_substr ($ str, $ len ){
   $ Count = 0;
   For ($ I = 0; $ I <strlen ($ str); $ I ++ ){
       If ($ count = $ len) break;
       If (preg_match ("/[\ x80-\ xff]/", substr ($ str, $ I, 1) ++ $ I;
       + + $ Count;      
   }
   Return substr ($ str, 0, $ I );
}

// Count the length of the string-UTF8 (PHP)
Function utf8_strlen ($ str ){
   $ Count = 0;
   For ($ I = 0; $ I <strlen ($ str); $ I ++ ){
       $ Value = ord ($ str [$ I]);
       If ($ value & gt; 127 ){
           $ Count ++;
           If ($ value >=192 & $ value <= 223) $ I ++;
           Elseif ($ value >=224 & $ value <= 239) $ I = $ I + 2;
           Elseif ($ value >=240 & $ value <= 247) $ I = $ I + 3;
           Else die ('not a UTF-8 compatible string ');
       }
       $ Count ++;
   }
   Return $ count;
}

// Truncate the string-UTF8 (PHP)
Function utf8_substr ($ str, $ position, $ length ){
   $ Start_position = strlen ($ str );
   $ Start_byte = 0;
   $ End_position = strlen ($ str );
   $ Count = 0;
   For ($ I = 0; $ I <strlen ($ str); $ I ++ ){
       If ($ count >=$ position & $ start_position> $ I ){
           $ Start_position = $ I;
           $ Start_byte = $ count;
       }
       If ($ count-$ start_byte)> = $ length ){
           $ End_position = $ I;
           Break;
       }  
       $ Value = ord ($ str [$ I]);
       If ($ value & gt; 127 ){
           $ Count ++;
           If ($ value >=192 & $ value <= 223) $ I ++;
           Elseif ($ value >=224 & $ value <= 239) $ I = $ I + 2;
           Elseif ($ value >=240 & $ value <= 247) $ I = $ I + 3;
           Else die ('not a UTF-8 compatible string ');
       }
       $ Count ++;

   }
   Return (substr ($ str, $ start_position, $ end_position-$ start_position ));
}

// String Length statistics-UTF8 [three Chinese characters, two Russian and Korean characters, and one letter] (Ruby)
Def utf8_string_length (str)
   Temp = CGI: unescape (str)
   I = 0;
   J = 0;
   Temp. length. times {| t |
       If temp [t] <127
           I + = 1
       Elseif temp [t]> = 127 and temp [t] <224
           J + = 1
           If 0 = (j % 2)
               I + = 2
               J = 0
           End
       Else
           J + = 1
           If 0 = (j % 3)
               I + = 2
               J = 0
           End
       End
   }
   Return I
}

// Determine if there is a Korean-UTF-8 (JavaScript)
Function checkKoreaChar (str ){
   For (I = 0; I <str. length; I ++ ){
       If (str. charCodeAt (I)> 0x3130 & str. charCodeAt (I) <0x318F) | (str. charCodeAt (I)> = 0xAC00 & str. charCodeAt (I) <= 0xD7A3 ))){
           Return true;
       }
   }
   Return false;
}
// Determine whether a Chinese character-GBK (JavaScript) exists)
Function check_chinese_char (s ){
   Return (s. length! = S. replace (/[^ \ x00-\ xff]/g, "**"). length );

Iii. References

In addition:

Public function csubstr ($ str, $ start = 0, $ length, $ charset = "UTF-8", $ suffix = true)
{
If (function_exists ("mb_substr "))
Return mb_substr ($ str, $ start, $ length, $ charset );
$ Re ['utf-8'] = "/[\ x01-\ x7f] | [\ xc2-\ xdf] [\ x80-\ xbf] | [\ xe0 -\ xef] [\ x80-\ xbf] {2} | [\ xf0-\ xff] [\ x80-\ xbf] {3 }/";
$ Re ['gb2312'] = "/[\ x01-\ x7f] | [\ xb0-\ xf7] [\ xa0-\ xfe]/";
$ Re ['gbk'] = "/[\ x01-\ x7f] | [\ x81-\ xfe] [\ x40-\ xfe]/";
$ Re ['big5'] = "/[\ x01-\ x7f] | [\ x81-\ xfe] ([\ x40-\ x7e] | \ xa1-\ xfe]) /";
Preg_match_all ($ re [$ charset], $ str, $ match );
$ Slice = join ("", array_slice ($ match [0], $ start, $ length ));
If ($ suffix) return $ slice ."... ";
Return $ slice;
}