perl匹配中文（简体繁体others）encode

use Encode;
use strict;

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

运行结果是:

程序代码:
2
6

这里咱们使用Encode模块的_utf8_on函数和_utf8_off函数来开关字符串"中国"的utf8 flag. 能够看到, utf8 flag打开的时候, "中国"被当成utf8字符串处理, 因此其长度是2. utf8 flag关闭的时候, "中国"被当成octets(字节数组)处理, 出来的长度是6(个人编辑器用的是utf8编码, 若是你的编辑器用的是gb2312编码, 那么长度应该是4).

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

encode函数顾名思义是用来编码Perl字符串的。它将Perl字符串中的字符用指定的编码格式编码，最终转化为字节流的形式，所以和Perl处理环境以外的事物打交道常常须要它。其格式很简单：
$octets = encode(ENCODING, $string [, CHECK])

decode函数则是用来解码字节流的。它按照你给出的编码格式解释给定的字节流，将其转化为使用utf8编码的Perl字符串，通常来讲从终端或者文件取得的文本数据都应该用decode转换为Perl字符串的形式。

use Encode;
use Encode::CN; #可写可不写
$dat="测试文本";
$str=decode("gb2312",$dat);
@chars=split //,$str;
foreach $char (@chars) {
    print encode("gb2312",$char),"/n";
}

一、查看可用编码

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));