如何在正则表达式中使用不同的分隔符(/、|) [英] How to use different separators (/ , |) in a regular expression

问题描述

修改一个Perl 脚本，我得到了这个:

Modifying a Perl script, i got this:

$var =~ s,/$,,;

这似乎是一个正则表达式模式，但我希望找到/"(或|")而不是，"作为分隔符.

it seems to be a regex pattern, but i was expecting to found "/" (or "|") instead of "," as separator.

所以问题是:何时以及为什么应该在正则表达式模式中使用/"或|"还是,"?

推荐答案

在 Perl 中，在替换操作符，以及许多其他操作符中，您几乎可以用定界符替换任何标点符号，例如

In Perl, in the substitution operator, as well as many other operators, you can substitute the delimiter for almost any punctuation character, such as

s#/$##
s=/$==
s!/$!!

何时使用哪个取决于您当时需要什么.最好选择一个与正则表达式中的字符不冲突的分隔符，并且是可读的.

Which one to use when is a matter of what you need at the time. Preferably you choose a delimiter that does not conflict with the characters in your regex, and one that is readable.

在您的情况下，使用了与 / 不同的分隔符，因为有人想在正则表达式中包含斜杠，以删除尾部斜杠.使用默认分隔符，它应该是:

In your case, a different delimiter from / was used because one wanted to include a slash in the regex, to remove a trailing slash. With the default delimiters, it would have been:

s/\/$//

这不是那么容易阅读.

就像我上面提到的，你可以用很多运算符和函数来做到这一点:

Like I mentioned above, you can do this with a great many operators and functions:

m#...#
qw/.../
qw#...#
tr;...;;
qq?...?

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