Re: About regular expression

[Trimbach]

First, you're missing a ~ character. It should be: -- Not necessary. There's an implicit match against $_.--geb

(code deleted)

Second, let's break it down:

my ($label) =~ /      # begin 
                  \.    # find a literal . 
                  (      # start capturing
                   [^\.] # Any character that isn't a \ or .
                   *    # zero or more
                   )      # stop capturing
                  $      # only match from the end of the string
                   /       # end;

In a nutshell this will match the "extension" of the data you provided, i.e. the "five" in "one.five" or the "12" in "two.ten.12". What's matched is captured into $label.

There's lots of info on regexes both here and in the regular Perl documentation. They can be challenging at first, but are well worth the effort to figure out. :-D

Gary Blackburn
Trained Killer

Edited

[abstracts]

Sorry, but I don't think there is a missing '~'. $label is assigned the matched between the parens (everything after the dot). It's not being matched by the re.

Aziz,,,

[Trimbach]

Yeah, you're right. There's an implicit match against $_ there that I didn't see. I guess it just wasn't implied enough. :-D

Gary Blackburn
Trained Killer

[Juerd]

[^\.] # Any character that isn't a \ or .

Not exactly. The backslash is used as an escape character, not only in the regex itself, but in character classes too. Even though it's not necessary at all to escape a dot in a character class, Perl removes the backslash itself (Perl always does something when you use a backspace in an interpolated string, unlike some languages where "\q\n" is backslash, q, newline. In Perl, "\q\n" is q, newline.).



[^\.] # Any character that is not .
[^.] # Any character that is not .

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W5kIHBhY2soKS4gQnV0IGRvIHlvdS
ByZWNvZ25pc2UgQmFzZTY0IHdoZW4
geW91IHNlZSBpdD8gIC0tIEp1ZXJk