in reply to Regexp substitution on variable-length ranges with embedded code?

You can use regex to extract the data, but I'd reach for something like Set::IntSpan to handle the intervals. 
#!/usr/bin/perl
use warnings;
use strict;

use Set::IntSpan;

my $data = '43:1:1; 43:1:2; 43:1:3; 43:1:4; 43:1:5; 43:1:6; 27:3:7; 27
+:3:8; 27:3:9; 65:1:4; 65:1:18';

my %result;
my $out = sub {
    my $key = (keys %result)[0] or return;
    print "$key:", delete $result{$key}, ';';
};
while ($data =~ /([0-9]+:[0-9]+):([0-9]+)/g) {
    my ($key, $value) = ($1, $2);
    if (exists $result{$key}) {
        $result{$key}->U($value);

    } else {
        $out->();
        $result{$key} = 'Set::IntSpan'->new($value);
    }
}
$out->();

[download]
Output: 
43:1:1-6;27:3:7-9;65:1:4,18;

[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

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Re^2: Regexp substitution on variable-length ranges with embedded code?
by Fletch (Bishop) on May 26, 2021 at 13:53 UTC

    I saw this and was going to reply with something to the effect of Set::IntSpan but I was too late and mine wouldn't have had as clever a trick with that closure coderef . . . bah.

    Also as far as the original question, IMHO most times if you're thinking about embedding code inside your regexen you're pretty well already deep into (quasi-apocryphical) JWZ-quote / xkcd 1171 territory.

    The cake is a lie.
    The cake is a lie.
    The cake is a lie.

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        I always had an admiration for that cat; solely based on his Netscape exit letter. After reading that roundup I must remark: Anyone who can earnestly write, “Perl is mostly terrible, maybe Java will save us,” cannot be taken seriously.

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