Can I use named groups in a Perl regex to get the results in a hash?

Question

Is it possible to perform a named-group match in Perl's regex syntax as with Python's? I always bind the $n values to proper names after matching, so I'd find it more convenient to do it in the regex itself if it's possible.

Python does it like so:

>>> import re >>> regex = re.compile(r'(?P<count>\d+)') >>> match = regex.match('42') >>> print match.groupdict() {'count': '42'} 

I know the ?P indicates that it's a Python-specific regex feature, but I'm hoping it's in Perl in a different way or was added later on. Is there any way to get a result hash in a similar manner in Perl?

Answer 1

Perl uses (?<NAME>pattern) to specify names captures. You have to use the %+ hash to retrieve them.

$variable =~ /(?<count>\d+)/; print "Count is $+{count}"; 

This is only supported on Perl 5.10 and higher though.

Answer 2

As of Perl 5.10, Perl regexes support some Python features, making them Python compatible regexes, I guess. The Python versions have the "P" in them, but all of these work in Perl 5.10. See the perlre documentation for the details:

Define a named capture buffer. Equivalent to (?<NAME>pattern).

(?P<NAME>pattern) 

Backreference to a named capture buffer. Equivalent to \g{NAME}.

(?P=NAME) 

Subroutine call to a named capture buffer. Equivalent to (?&NAME).

(?P>NAME) 

Although I didn't add the Python-compatibility to the latest edition of Learning Perl, we do cover the new Perl 5.10 features, including named captures.