Perl,使用tr函数将大写转换为小写,反之亦然？

Question

我有一个字符串

$string= 'AbCdEf';

我想使用tr函数将所有大写字母转换为小写字母,将所有小写字母转换为大写字母....同时.我基本上只想扭转它成为.

aBcDeF

我提出了这条线,但我不知道如何修改它来做我想要的.有什么帮助吗？

$string=~ tr/A-Z/a-z/;

谢谢!

Answer 1

在Tom的请求下,Unicode-clean(或locales-clean)版本:

s/([[:upper:]])|([[:lower:]])/defined $1 ? lc $1 : uc $2/eg

Answer 2

$string =~ tr/A-Za-z/a-zA-Z/;

Answer 3

您可以这样做完整的Unicode解决方案:

    s/ (\p{CWU}) | (\p{CWL}) /defined $1 ? uc $1 : lc $2/gex;

或者这样

    s/ (\p{CWL}) | (\p{CWU}) /defined $1 ? lc $1 : uc $2/gex;

取决于你想要做什么来改变两个方向的情况,比如Dz,其大写字母是DZ,小写字母是dz.

如果您在此输入中运行这两个替换中的第二个:

     @   0040  COMMERCIAL AT
     ©   00A9  COPYRIGHT SIGN
     Å   212B  ANGSTROM SIGN
     ?   249C  PARENTHESIZED LATIN SMALL LETTER A
     ?   24B6  CIRCLED LATIN CAPITAL LETTER A
     ?   24D0  CIRCLED LATIN SMALL LETTER A
     ?  FF21  FULLWIDTH LATIN CAPITAL LETTER A
     ?  FF41  FULLWIDTH LATIN SMALL LETTER A
     ?   24B8  CIRCLED LATIN CAPITAL LETTER C
     ?   24D2  CIRCLED LATIN SMALL LETTER C
     ?   01F1  LATIN CAPITAL LETTER DZ
     ?   01F2  LATIN CAPITAL LETTER D WITH SMALL LETTER Z
     ?   01F3  LATIN SMALL LETTER DZ
     ?   2172  SMALL ROMAN NUMERAL THREE
     S   0053  LATIN CAPITAL LETTER S
     s   0073  LATIN SMALL LETTER S
     ?   017F  LATIN SMALL LETTER LONG S
     ?   24AE  PARENTHESIZED LATIN SMALL LETTER S
     ?   24C8  CIRCLED LATIN CAPITAL LETTER S
     ?   24E2  CIRCLED LATIN SMALL LETTER S
     ?   A784  LATIN CAPITAL LETTER INSULAR S
     ?   A785  LATIN SMALL LETTER INSULAR S
     ß   00DF  LATIN SMALL LETTER SHARP S
     ?   1E9E  LATIN CAPITAL LETTER SHARP S
     ?   2166  ROMAN NUMERAL SEVEN
     ?   217B  SMALL ROMAN NUMERAL TWELVE

它会产生以下结果:

     @   0040  commercial at
     ©   00a9  copyright sign
     å   212b  angstrom sign
     ?   249c  parenthesized latin small letter a
     ?   24b6  circled latin capital letter a
     ?   24d0  circled latin small letter a
     ?  ff21  fullwidth latin capital letter a
     ?  ff41  fullwidth latin small letter a
     ?   24b8  circled latin capital letter c
     ?   24d2  circled latin small letter c
     ?   01f1  latin capital letter dz
     ?   01f2  latin capital letter d with small letter z
     ?   01f3  latin small letter dz
     ?   2172  small roman numeral three
     s   0053  latin capital letter s
     S   0073  latin small letter s
     S   017f  latin small letter long s
     ?   24ae  parenthesized latin small letter s
     ?   24c8  circled latin capital letter s
     ?   24e2  circled latin small letter s
     ?   a784  latin capital letter insular s
     ?   a785  latin small letter insular s
     SS   00df  latin small letter sharp s
     ß   1e9e  latin capital letter sharp s
     ?   2166  roman numeral seven
     ?   217b  small roman numeral twelve

使用第一个函数的唯一不同的部分(在该集合中)将是dz序列看起来像这样:

     ?   01f1  latin capital letter dz
     ?   01f2  latin capital letter d with small letter z
     ?   01f3  latin small letter dz

你不想只使用上限或下限测试的原因是因为你做了不必要的工作,因为有很多套管代码点在casemapped时不会改变大小写.例如,所有这些都是套管代码点,但在大写时和小写时都不会改变:

     ª   00AA FEMININE ORDINAL INDICATOR
     ?   1D2C MODIFIER LETTER CAPITAL A
     ?   1D00 LATIN LETTER SMALL CAPITAL A
     ?   2102 DOUBLE-STRUCK CAPITAL C
     ?   1D30 MODIFIER LETTER CAPITAL D 
     ?   02A3 LATIN SMALL LETTER DZ DIGRAPH
     ?   02A4 LATIN SMALL LETTER DEZH DIGRAPH
     ?   2107 EULER CONSTANT
     ?   0258 LATIN SMALL LETTER REVERSED E
     ?   025E LATIN SMALL LETTER CLOSED REVERSED OPEN E
     ?   210A SCRIPT SMALL G
     ?   0261 LATIN SMALL LETTER SCRIPT G
     ?   0262 LATIN LETTER SMALL CAPITAL G
     ?   02B0 MODIFIER LETTER SMALL H
     ?   210B SCRIPT CAPITAL H
     ?   210E PLANCK CONSTANT 
     ?   2139 INFORMATION SOURCE
     ?   02B2 MODIFIER LETTER SMALL J
     ?   2133 SCRIPT CAPITAL M
     º   00BA MASCULINE ORDINAL INDICATOR
     ?   0278 LATIN SMALL LETTER PHI
     ?   0138 LATIN SMALL LETTER KRA
     ?   028F LATIN LETTER SMALL CAPITAL Y
     ?   213C DOUBLE-STRUCK SMALL PI

所以你会发现它们是大写或小写,然后调用逆映射函数,然后发现没有任何改变.我想,为什么要这么麻烦？