use strict;
use warnings;
use Tk;

my $mw = tkinit();
my @radiobuttons;
my $var;
for my $v( 1 .. 5 ) {
    my $rb = $mw->Radiobutton( -variable => \$var, -text => $v, -value => $v );
    $rb->pack;
    
    push @radiobuttons, $rb;
}

$radiobuttons[3]->select;

MainLoop;