Match entires and seaprate by bracket before writing

use strict;
use warnings;

my $file1 = 'file1.txt';
my $file2 = 'file2.txt';

open my $f1_fh, '<', $file1 or die "failed to open $file1 $!";
open my $f2_fh, '<', $file2 or die "failed to open $file2 $!";

my %data;

while ( my $line = <$f1_fh> ) {
    chomp $line;
    my ($key, $value) = split /\s+/, $line, 2;
    $data{$key} = $value;
}
close $f1_fh;

while ( my $line = <$f2_fh> ) {
    chomp $line;
    my ($key, $value) = split /\s+/, $line, 2;
    my @parts = map { $data{$_} ? "$_ ($data{$_})" : $_ } split /, /, $value;
    
    printf "%s\t%s\n", $key, join(', ', @parts);
}
close $f2_fh;

Original - Perl Code $data{$key} = $value if defined $value;

$data{$key} = $value if defined $value;