Re: Duplicate Results from Subroutine

[stephen]

To fix this specific problem, you need to localize @cands in abv() rather than up at the top of the script.

sub abv
{
    # Move from top of the script down to here
    my @cands = ();
    foreach my $cand (@numlist) {
        if ($cand > $numlist_avg) {
            push(@cands, $cand);
        }
    }
    return @cands;
}

Each time you call abv(), it remembers @cands from the last time you call it, and returns the duplicate values as well as the new ones.

It's a good idea to localize your variables to the smallest possible block. Declare them in the subroutine that's using them.

You're also assuming that $numlist_avg has already been determined. If you tried calling abv() before setting $numlist_avg, you might wind up with a hard-to-trace error.

While we're at it, you're passing @numlist to the subroutine as an argument, but not actually using that argument. If you called abv(1,2,3) it would still go over @numlist to get the result. So, instead, you should do:

sub abv
{
    my (@numlist_args) = @_;

    my @cands = ();

    my $avg = avg(@numlist_args);

    foreach my $cand (@numlist_args) {
        if ($cand > $avg) {
            push(@cands, $cand);
        }
    }
    return @cands;
}

Good luck!

[zenrhino]

Daaaang.

That's like five lessons for the price of one.
I did bang my head against ways to generalize the subroutines not using @numlist, but figured asking two questions at once would be selfish.

So if I have this right, @_ holds the list of parameters passed to the abv subroutine, and we know it gets passed as a list because it ends up as my (@numlist_args) and not my @numlist_args which would pass a scalar. So then the foreach loop works on whatever is passed as paramaters.

I took your help and also applied it to the std_dev subroutine which had the effect of letting me get rid of all of the hardcoded variables that I had originally and making the subroutines easier to read.

Thank you very much!

-Clint

[Koshatul]

So if I have this right, @_ holds the list of parameters passed to the abv subroutine.

You got it, here's a version that uses the special variables $_ and @_

sub abv {
    my $avg = avg(@_);
    my @cands = ();
    foreach (@_) {
        ($_ > $avg) and push(@cands, $_);
    }
    return @cands;
}

I flicked the if statement into a logical and, for each iteration of the foreach $_ will be the same as $cand was in the original function.

[choroba]

Or, simplified by grep:

sub abv {
    my $avg = avg(@_);
    return grep $_ > $avg, @_;
}