如何识别Perl中的货币符号？

Question

我遇到了一些麻烦.

我正在读一些文字并试图从中提取价格.我很好,但我正在尝试编写一些代码来确定文本中符号的货币名称,if语句类似于这些

if ($curr eq "\$"){
print CURRENCY "Currency: Dollars($curr)\n";
}
else {if($curr eq "£"){
print CURRENCY  "Currency: Pounds($curr)\n";
}
else {if($curr eq "€"){
print CURRENCY  "Currency: Euros($curr)\n";
}

现在这适用于$(必须明显地转义),但不适用于英镑符号或欧元符号.我认为这与Unicode编码有关,或类似于我试图谷歌提出的问题,但我找不到任何帮助.我想知道是否有人可以帮助我!

Answer 1

如何谈论Unicode字符

听起来你的编码有问题.您似乎在Perl程序的源代码中有Unicode字符.你需要使用这个pragma(这是一种说明小写模块名称,类似于编译器指令的奇特方式):

use utf8;

将它放在程序的顶部,然后确保您实际上正在使用一个知道将其保存为UTF-8文本的编辑器进行编辑.您可以使用该file命令验证它是否表明该文件是UTF-8.

不要求Perl源为UTF-8的替代方法是使用代码点编号或Unicode字符名称而不是文字.要获取命名的Unicode字符,请使用此pragma:

use charnames qw[ :full ];

现在您可以使用"\N{…}"符号来谈论命名字符:

$pound_sign = "\N{POUND SIGN}";
$euro_sign  = "\N{EURO SIGN}";

另一种方法是使用数字代码点,如果你知道它:

$pound_sign = chr(163);
$euro_sign  = chr(0x20AC);

如果需要,您也可以使用字符串和模式中的确切数字:

if ($text =~ /\xA3/) { … }     # POUND SIGN

if ($text =~ /\x{20AC}/) { … } # EURO SIGN

这将使你不必在你的Perl源代码中放入非ASCII,这可能是一个好主意,即使像这样的文字幻数可能不是.但是,您仍需要考虑您的数据源是否采用某种编码方式.我将假设它采用一些Unicode编码,可能是UTF-8.我希望它不是Oracle的CESU-8或Java的"修改过的UTF-8".

Unicode'Furrency_Symbol'属性

检测由单个Unicode字符在文本中表示的任何任意货币符号的唯一正确方法是检测Unicode货币符号属性,\p{Sc}或\p{Currency_Symbol}.

这些是Unicode属性,它们是可以在正则表达式中使用的字符类.

你会想说些什么

if ($curr =~ /^\p{Sc}$/) { ... }

但要实现这一点,您必须$curr从:utf8编码中的输入源读入.在你自己的来源中,你会说:

use utf8;

在你打开的文件中,你会说其中一个:

# put at the top of your file and be done with it
use open qw[ :std :utf8 ];

# or else when opening a new handle
open(my $new_handle, "< :encoding(utf8)", "/path/to/file")
    || die "can't open /path/to/file: $!";

# if handle already opened, then just
binmode($already_opened_handle, ":encoding(utf8)")
     || die "can't binmode: $!";

从技术上讲,:encoding(utf8)除了use utf8;你自己的源文件之外,你应该使用它,这样你就不会被欺骗了.不要问.☹

如果你使用像一个模块CGI.pm或者XML::Simple,它应该只是工作-但它依赖.

货币符号字符的属性

这是完整的交易:

% uniprops -vag € 'POUND SIGN'
U+20AC ‹€› \N{ EURO SIGN }:
    \p{\pS} \p{\p{Sc}}
    \p{All} \p{Any} \p{Assigned} \p{InCurrencySymbols} \p{Common} \p{Zyyy} \p{Currency_Symbol} \p{Sc} \p{S} \p{Gr_Base} \p{Grapheme_Base} \p{Graph}
       \p{GrBase} \p{Print} \p{Symbol}
    \p{Age:2.1} \p{Bidi_Class:ET} \p{Bidi_Class=European_Terminator} \p{Bidi_Class:European_Terminator} \p{Bc=ET} \p{Block:Currency_Symbols}
       \p{Canonical_Combining_Class:0} \p{Canonical_Combining_Class=Not_Reordered} \p{Canonical_Combining_Class:Not_Reordered} \p{Ccc=NR}
       \p{Canonical_Combining_Class:NR} \p{Script=Common} \p{General_Category=Currency_Symbol} \p{Decomposition_Type:None} \p{Dt=None} \p{East_Asian_Width:A}
       \p{East_Asian_Width=Ambiguous} \p{East_Asian_Width:Ambiguous} \p{Ea=A} \p{General_Category:Currency_Symbol} \p{Gc=Sc} \p{General_Category:S}
       \p{General_Category=Symbol} \p{General_Category:Sc} \p{General_Category:Symbol} \p{Gc=S} \p{Grapheme_Cluster_Break:Other} \p{GCB=XX}
       \p{Grapheme_Cluster_Break:XX} \p{Grapheme_Cluster_Break=Other} \p{Hangul_Syllable_Type:NA} \p{Hangul_Syllable_Type=Not_Applicable}
       \p{Hangul_Syllable_Type:Not_Applicable} \p{Hst=NA} \p{Joining_Group:No_Joining_Group} \p{Jg=NoJoiningGroup} \p{Joining_Type:Non_Joining} \p{Jt=U}
       \p{Joining_Type:U} \p{Joining_Type=Non_Joining} \p{Line_Break:PR} \p{Line_Break=Prefix_Numeric} \p{Line_Break:Prefix_Numeric} \p{Lb=PR}
       \p{Numeric_Type:None} \p{Nt=None} \p{Numeric_Value:NaN} \p{Nv=NaN} \p{Present_In:2.1} \p{In=2.1} \p{Present_In:3.0} \p{In=3.0} \p{Present_In:3.1}
       \p{In=3.1} \p{Present_In:3.2} \p{In=3.2} \p{Present_In:4.0} \p{In=4.0} \p{Present_In:4.1} \p{In=4.1} \p{Present_In:5.0} \p{In=5.0} \p{Present_In:5.1}
       \p{In=5.1} \p{Present_In:5.2} \p{In=5.2} \p{Script:Common} \p{Sc=Zyyy} \p{Script:Zyyy} \p{Sentence_Break:Other} \p{SB=XX} \p{Sentence_Break:XX}
       \p{Sentence_Break=Other} \p{Word_Break:Other} \p{WB=XX} \p{Word_Break:XX} \p{Word_Break=Other}
U+00A3 ‹£› \N{ POUND SIGN }:
    \p{\pS} \p{\p{Sc}}
    \p{All} \p{Any} \p{Assigned} \p{InLatin1} \p{Common} \p{Zyyy} \p{Currency_Symbol} \p{Sc} \p{S} \p{Gr_Base} \p{Grapheme_Base} \p{Graph} \p{GrBase}
       \p{Pat_Syn} \p{Pattern_Syntax} \p{PatSyn} \p{Print} \p{Symbol}
    \p{Age:1.1} \p{Bidi_Class:ET} \p{Bidi_Class=European_Terminator} \p{Bidi_Class:European_Terminator} \p{Bc=ET} \p{Block:Latin_1}
       \p{Block=Latin_1_Supplement} \p{Block:Latin_1_Supplement} \p{Blk=Latin1} \p{Canonical_Combining_Class:0} \p{Canonical_Combining_Class=Not_Reordered}
       \p{Canonical_Combining_Class:Not_Reordered} \p{Ccc=NR} \p{Canonical_Combining_Class:NR} \p{Script=Common} \p{General_Category=Currency_Symbol}
       \p{Decomposition_Type:None} \p{Dt=None} \p{East_Asian_Width:Na} \p{East_Asian_Width=Narrow} \p{East_Asian_Width:Narrow} \p{Ea=Na}
       \p{General_Category:Currency_Symbol} \p{Gc=Sc} \p{General_Category:S} \p{General_Category=Symbol} \p{General_Category:Sc} \p{General_Category:Symbol}
       \p{Gc=S} \p{Grapheme_Cluster_Break:Other} \p{GCB=XX} \p{Grapheme_Cluster_Break:XX} \p{Grapheme_Cluster_Break=Other} \p{Hangul_Syllable_Type:NA}
       \p{Hangul_Syllable_Type=Not_Applicable} \p{Hangul_Syllable_Type:Not_Applicable} \p{Hst=NA} \p{Joining_Group:No_Joining_Group} \p{Jg=NoJoiningGroup}
       \p{Joining_Type:Non_Joining} \p{Jt=U} \p{Joining_Type:U} \p{Joining_Type=Non_Joining} \p{Line_Break:PR} \p{Line_Break=Prefix_Numeric}
       \p{Line_Break:Prefix_Numeric} \p{Lb=PR} \p{Numeric_Type:None} \p{Nt=None} \p{Numeric_Value:NaN} \p{Nv=NaN} \p{Present_In:1.1} \p{Age=1.1} \p{In=1.1}
       \p{Present_In:2.0} \p{In=2.0} \p{Present_In:2.1} \p{In=2.1} \p{Present_In:3.0} \p{In=3.0} \p{Present_In:3.1} \p{In=3.1} \p{Present_In:3.2} \p{In=3.2}
       \p{Present_In:4.0} \p{In=4.0} \p{Present_In:4.1} \p{In=4.1} \p{Present_In:5.0} \p{In=5.0} \p{Present_In:5.1} \p{In=5.1} \p{Present_In:5.2} \p{In=5.2}
       \p{Script:Common} \p{Sc=Zyyy} \p{Script:Zyyy} \p{Sentence_Break:Other} \p{SB=XX} \p{Sentence_Break:XX} \p{Sentence_Break=Other} \p{Word_Break:Other}
       \p{WB=XX} \p{Word_Break:XX} \p{Word_Break=Other}

查找所有\ p {Sc}个字符

以下是带有Scaka Currency_Symbol属性的所有46个Unicode字符,当前的Unicode 5.2 :( 对不起格式化问题;我认为这是由于方向性)

 % unichars -a '\p{Sc}' | wc -l
       46

 % unichars -a '\p{Sc}'
 $      36 000024 DOLLAR SIGN
 ¢     162 0000A2 CENT SIGN
 £     163 0000A3 POUND SIGN
 ¤     164 0000A4 CURRENCY SIGN
 ¥     165 0000A5 YEN SIGN
 ?    1547 00060B AFGHANI SIGN
 ?    2546 0009F2 BENGALI RUPEE MARK
 ?    2547 0009F3 BENGALI RUPEE SIGN
 ?    2555 0009FB BENGALI GANDA MARK
 ?    2801 000AF1 GUJARATI RUPEE SIGN
 ?    3065 000BF9 TAMIL RUPEE SIGN
 ?    3647 000E3F THAI CURRENCY SYMBOL BAHT
 ?    6107 0017DB KHMER CURRENCY SYMBOL RIEL
 ?    8352 0020A0 EURO-CURRENCY SIGN
 ?    8353 0020A1 COLON SIGN
 ?    8354 0020A2 CRUZEIRO SIGN
 ?    8355 0020A3 FRENCH FRANC SIGN
 ?    8356 0020A4 LIRA SIGN
 ?    8357 0020A5 MILL SIGN
 ?    8358 0020A6 NAIRA SIGN
 ?    8359 0020A7 PESETA SIGN
 ?    8360 0020A8 RUPEE SIGN
 ?    8361 0020A9 WON SIGN
 ?    8362 0020AA NEW SHEQEL SIGN
 ?    8363 0020AB DONG SIGN
 €    8364 0020AC EURO SIGN
 ?    8365 0020AD KIP SIGN
 ?    8366 0020AE TUGRIK SIGN
 ?    8367 0020AF DRACHMA SIGN
 ?    8368 0020B0 GERMAN PENNY SIGN
 ?    8369 0020B1 PESO SIGN
 ?    8370 0020B2 GUARANI SIGN
 ?    8371 0020B3 AUSTRAL SIGN
 ?    8372 0020B4 HRYVNIA SIGN
 ?    8373 0020B5 CEDI SIGN
 ?    8374 0020B6 LIVRE TOURNOIS SIGN
 ?    8375 0020B7 SPESMILO SIGN
 ?    8376 0020B8 TENGE SIGN
 ?   43064 00A838 NORTH INDIC RUPEE MARK
 ?   65020 00FDFC RIAL SIGN
 ?   65129 00FE69 SMALL DOLLAR SIGN
 ?   65284 00FF04 FULLWIDTH DOLLAR SIGN
 ?   65504 00FFE0 FULLWIDTH CENT SIGN
 ?   65505 00FFE1 FULLWIDTH POUND SIGN
 ?   65509 00FFE5 FULLWIDTH YEN SIGN
 ?   65510 00FFE6 FULLWIDTH WON SIGN

而BMP中的那些还没有在Unicode 4.1中; 注意如何组合属性和否定来拉取Unicode字符集.

% unichars --bmp '\p{Sc}' '\P{In:4.1}'
 ?  2555 09FB BENGALI GANDA MARK
 ?  8374 20B6 LIVRE TOURNOIS SIGN
 ?  8375 20B7 SPESMILO SIGN
 ?  8376 20B8 TENGE SIGN
 ? 43064 A838 NORTH INDIC RUPEE MARK

如果您没有unichars和uniprops您的系统,只需发送邮件,我会发送给您.它们是纯Perl中的小型实用程序,不需要额外的模块.