Mathematical averages

[arrow]

Greetings Perl Monks! I'm working on a rather simple script, but one small part keeps giving me trouble. It is supposed to give an average, but skip nonexistant entries. Maybe I can explain better with the actual code:

for (my $num = $members) {
foreach $month2 (@calendar) {
foreach $name2 (@members) {
if ($hoursWorked{$name2}{$month2} == 0) {
$num--; #this is to protect against false averages, because $members w
+ill usually have a value of 13, but I don't want to count the zero va
+lues because is would result in an incorrect average, (i.e. 24/6 inst
+ead of 24/13 because only 6 people worked)

$avg{$month2} += $hoursWorked{$name2}{$month2};
}
}
if ($num == 0) {
$avg{$month2} = 0;
}
else {
$avg{$month2} = $avg{$month2}/$num;
}
}
}

Right now, the problem is that it prints the incorrect averages, like 0 instead of 12. I'm sorry if I couldn't explain well, I barely understand what's going on myself. Anyone have any suggestions?

Just Another Perl Wannabe

[dpuu]

I think your problem is the initial assignment to $num. Your code is confused: that C<for> statement is not a loop, its just an assignment. But the assignment should be inside the month loop, because you are calculating the average per month. A clearer coding of this might be:

  foreach my $month (@calendar)
  {
    my $count = 0;
    my $total = 0;

    foreach my $value (
         grep { $_ != 0 }
         map { $hoursWorked{$_}{$month} }
         @members )
    {
       $total += $value;
       $count ++;
    }

    $avg{$month} = $count ? $total/$count : 0;
  }

--Dave

[dws]

This line     for (my $num = $members) { raises a flag. I would expect to see something like     for my $num ( @members ) { or, if members is a reference to an array,     for my $num ( @$members ) { Instead, what's there is basically a one-trip loop, which leads me to suspect that this isn't what you intended.

[arrow]

Hey, thanks so much dws and dpuu, your answers where just the thing I need. I was surprised at how dpuu's answer worked so well and fast (sorry dws, I just used dpuu's suggesstion first). Anyway, thank you again for saving my butt!

Just Another Perl Wannabe