my %idx = ();
my $val = 0;
my @num = ();
my $nrndded = 3;
my $ulmt = 10;
while(scalar keys %idx < $nrneeded){
    $val = int(rand($ulmt-1)+1);   # map range to (1..ulmt)
    $idx{$val} ||= 1 && push @num, $val;
}