sub test2
{
    my ($var2) = shift;
   
    # Perl can implement the if/else idea very code efficiently.
    
    return ("One")    if ($var2 =~ /^1\./ );
    return ("Two")    if ($var2 =~ /^2\./ );
    return ("Three")  if ($var2 =~ /^3\./ );
    return ("UNKOWN");
}

print test2 ("1.00.000"), "\n";
print test2 ("11.00.000"), "\n";
print test2 ("3.abc"),     "\n";

__END__
prints:
One
UNKOWN
Three