perl匹配中文（簡體繁體others）encode

use Encode;
use strict;

my $str = "中國";
Encode::_utf8_on($str);
print length($str) . "\n";
Encode::_utf8_off($str);
print length($str) . "\n";

運行結果是:

程序代碼:
2
6

這裏咱們使用Encode模塊的_utf8_on函數和_utf8_off函數來開關字符串"中國"的utf8 flag. 能夠看到, utf8 flag打開的時候, "中國"被當成utf8字符串處理, 因此其長度是2. utf8 flag關閉的時候, "中國"被當成octets(字節數組)處理, 出來的長度是6(個人編輯器用的是utf8編碼, 若是你的編輯器用的是gb2312編碼, 那麼長度應該是4).

# gb2312 encoding  chinese
use Encode;
my $a = "china----中國";
my $b = "china----中國";
my $stra = decode("gb2312",$a);
$stra =~ s/\W+//g;
print encode("gb2312",$stra),"\n"; 
輸出：
china中國

encode函數顧名思義是用來編碼Perl字符串的。它將Perl字符串中的字符用指定的編碼格式編碼，最終轉化爲字節流的形式，所以和Perl處理環境以外的事物打交道常常須要它。其格式很簡單：
$octets = encode(ENCODING, $string [, CHECK])

decode函數則是用來解碼字節流的。它按照你給出的編碼格式解釋給定的字節流，將其轉化爲使用utf8編碼的Perl字符串，通常來講從終端或者文件取得的文本數據都應該用decode轉換爲Perl字符串的形式。

use Encode;
use Encode::CN; #可寫可不寫
$dat="測試文本";
$str=decode("gb2312",$dat);
@chars=split //,$str;
foreach $char (@chars) {
    print encode("gb2312",$char),"/n";
}

一、查看可用編碼

use Encode;
#Returns a list of canonical names of available encodings that have already been loaded
@list = Encode->encodings();
#get a list of all available encodings including those that have not yet been loaded
@all_encodings = Encode->encodings(":all");
#give the name of a specific module
@with_jp = Encode->encodings("Encode::JP");
@ebcdic = Encode->encodings("EBCDIC");
print "@list\n";
print "@all_encodings\n";

二、

Character :A character in the range 0 .. 2**32-1 (or more); what Perl's strings are made of.

byte :A character in the range 0..255; a special case of a Perl character.

octet :8 bits of data, with ordinal values 0..255; term for bytes passed to or from a non-Perl context, such as a disk file, standard I/O stream, database, command-line argument, environment variable, socket etc.

三、perl Encoding API:encode decode

#convert a string from Perl's internal format into ISO-8859-1
$octets = encode("iso-8859-1", $string);

#convert ISO-8859-1 data into a string in Perl's internal format
$string = decode("iso-8859-1", $octets);

四、 perl Encoding API:find_encoding

Returns the encoding object corresponding to ENCODING. Returns undef if no matching ENCODING is find. The returned object is what does the actual encoding or decoding.

my $enc = find_encoding("iso-8859-1");
while(<>) {
     my $utf8 = $enc->decode($_);
     ... # now do something with $utf8;
}

find_encoding("latin1")->name; # iso-8859-1

五、perl Encoding API:from_to

[$length =] from_to($octets, FROM_ENC, TO_ENC [, CHECK])

from_to($octets, "iso-8859-1", "cp1250");

from_to($data, "iso-8859-1", "utf8"); #equal to
$data = encode("utf8", decode("iso-8859-1", $data));