Hello Monks! I am practicing perl by picking up text parsing questions from Stack Overflow. I came across a question where I had to transpose column such that following dataset

id1    name1 cat1  catname1
id1    name1 cat2  catname2
id2    name2 cat3  catname3
id3    name3 cat1  catname1
id3    name3 cat4  catname4

[download]

would become

id1    name1 cat1:catname1, cat2:catname2
id2    name2 cat3:catname3
id3    name3 cat1:catname1, cat4:catname4

[download]

I wrote a perl script, and even though it works as expected, I am in need of some wisdom. I wanted to know if there is a more idiomatic way of doing:

my @val = split(" ",$val);
my $v = join (":", @val);

[download]

and

if (exists $hash{$key}) {
    $hash{$key} .= $sep.$v;
}
else {
    $hash{$key} = $v;
}

[download]

Here is my complete perl script. Any advice and or suggestion to improve this will be greatly appreciated. This is my first post here at perlmonks, so if I missed on any crucial details, I apologize for that. Looking forward to be hearing from perlmonks. 

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my %hash;
my $sep = ", ";

while (<DATA>) {
    chomp;
    (my $key, my $val) = /(\S*\s*\S*\s*)(\S*\s*\S*\s*)/;
    my @val = split(" ",$val);
    my $v = join (":", @val);
    if (exists $hash{$key}) {
        $hash{$key} .= $sep.$v;
    }
    else {
        $hash{$key} = $v;
    }
}

foreach my $k (sort keys %hash) {
    print $k.$hash{$k}."\n";
}

#print Dumper \%h;

__DATA__
id1    name1 cat1  catname1
id1    name1 cat2  catname2
id2    name2 cat3  catname3
id3    name3 cat1  catname1
id3    name3 cat4  catname4

[download]

I could have used better variable names but this was just for practice so didn't really focus on that part.

In reply to Appending values to existing hash key by jaypal

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