用正则表达式判断各种文字字符

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PHP中GBK和UTF8编码处理

一、编码范围

1. GBK (GB2312/GB18030)
/x00-/xff  GBK双字节编码范围
/x20-/x7f  ASCII
/xa1-/xff  中文
/x80-/xff  中文

2. UTF-8 (Unicode)
/u4e00-/u9fa5 (中文)
/x3130-/x318F (韩文
/xAC00-/xD7A3 (韩文)
/u0800-/u4e00 (日文)
ps: 韩文是大于[/u9fa5]的字符

正则例子:
preg_replace("/([/x80-/xff])/","",$str);
preg_replace("/([u4e00-u9fa5])/","",$str);

 

二、代码例子

//判断内容里有没有中文-GBK (PHP)
function check_is_chinese($s){
    returnpreg_match('/[/x80-/xff]./', $s);
}

//获取字符串长度-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;
}

//截取字符串字串-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;
       ++$count;       
    }
    returnsubstr($str, 0, $i);
}

//统计字符串长度-UTF8 (PHP)
function utf8_strlen($str) {
    $count =0;
    for($i = 0;$i < strlen($str); $i++){
       $value = ord($str[$i]);
       if($value > 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;
}

//截取字符串-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 > 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));
}

//字符串长度统计-UTF8 [中文3个字节，俄文、韩文占2个字节，字母占1个字节] (Ruby)
def utf8_string_length(str)
    temp =CGI::(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
    }
    returni
}

//判断是否是有韩文-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;
       }
    }
    returnfalse;
}
//判断是否有中文字符-GBK (JavaScript)
function check_chinese_char(s){
    return(s.length != s.replace(/[^/x00-/xff]/g,"**").length);

 

三、参考文档

另：

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;
}