Re: How do I reference repeated capture groups?

Welcome to the Monastery.

You actually want to capture zero or more instances of '(\s*\d+\s*)'; i.e. '((?:\s*\d+\s*)*)'.

Your OP code:

$ perl -E '
    my $re = qr{(\w+)(\s*\d+\s*)*};
    my $str = "a 1 2 3 b 4 5 6";

    while ($str =~ /$re/g) {
        say "$&: $1 $2";
    }
'
a 1 2 3 : a 3
b 4 5 6: b 6
[download]

With fixed regex:

$ perl -E '
    my $re = qr{(\w+)((?:\s*\d+\s*)*)};
    my $str = "a 1 2 3 b 4 5 6";

    while ($str =~ /$re/g) {
        say "$&: $1 $2";
    }
'
a 1 2 3 : a  1 2 3
b 4 5 6: b  4 5 6
[download]

Named captures don't change the regex logic. The start of capture groups changes from '(' to '(?<name>'; and, accessing values changes from '$N' to '$+{name}'.

$ perl -E '
    my $re = qr{(?<letter>\w+)(?<digit>(?:\s*\d+\s*)*)};
    my $str = "a 1 2 3 b 4 5 6";

    while ($str =~ /$re/g) {
        say "$&: $+{letter} $+{digit}";
    }
'
a 1 2 3 : a  1 2 3
b 4 5 6: b  4 5 6
[download]

— Ken

Comment on Re: How do I reference repeated capture groups? Select or Download Code

Replies are listed 'Best First'.
Re^2: How do I reference repeated capture groups? by kcott (Archbishop) on Aug 13, 2022 at 03:03 UTC
It's not specifically part of your question; however, it occurs to me that you might not want to capture all that excess leading and trailing whitespace. Compare these: `$ perl -E ' my $re = qr{(\w+)((?:\s\d+\s))}; my $str = "a 1 2 3 b 4 5 6"; while ($str =~ /$re/g) { say "\|$&\|: \|$1\| \|$2\|"; } ' \|a 1 2 3 \|: \|a\| \| 1 2 3 \| \|b 4 5 6\|: \|b\| \| 4 5 6\|` [download] `$ perl -E ' my $re = qr{(\w+)\s+((?:\s\d+)*)}; my $str = "a 1 2 3 b 4 5 6"; while ($str =~ /$re/g) { say "\|$&\|: \|$1\| \|$2\|"; } ' \|a 1 2 3\|: \|a\| \|1 2 3\| \|b 4 5 6\|: \|b\| \|4 5 6\|` [download] — Ken	[reply] [d/l] [select]
Re^2: How do I reference repeated capture groups? by Anonymous Monk on Aug 13, 2022 at 20:08 UTC
from the original discussion on Reddit: Okay but I also just want a list of each of the matches so I can parse them separately. Think attributes in html, a tag can have multiple, and being able to handle each individually is useful ... that still doesn't give me `(a => [1, 2, 3], b => [4, 5, 6])` where in my analogy the letters are the html tags and the numbers are the attributes your answer with "1 2 3" in a string has already been given multiple times. BTW: The OP's moniker is Timegazer not Onion	[reply] [d/l]


Come for the quick hacks, stay for the epiphanies.
	PerlMonks