http://www.perlmonks.org?node_id=11105578


in reply to Re^2: sub as mathematical function
in thread sub as mathematical function

I linked to the documentation of the modulo operator. Your subroutine basically seems to do:

sub mod_9 {
    my( $x ) = @_;
    return $x % 9
}

[download]

Update: No, I misread the original function. You seem to input a number with decimals and want to know into which 9-tile it falls. int ($x*9)-1, as LanX notes below, is the correct answer then.

In Section Seekers of Perl Wisdom