Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Can someone tell me why I am getting an illegal division by zero error on this? The error is with $ctr and it dies in it's present state. When I comment it out and use my $ctr = "4", it works.

As for the values, here's a print out of the only hash key I have so far: 

6       fface.gif       http://www.go.com     19     8    4

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foreach (sort keys %db)
{
   my ($starttime, $filename, $pageurl, $exposure, $clicks) = split(/\
+|\|/, $db{$_});
   my $ctr = $clicks / $exposures * 100;
   #my $ctr = "4";
   $ctr =~ s/(\.\d\d)\d*/$1/;

    print <<"ALL";
    <tr>
    <td>$_</td>
    <td><center>$filename</center></td>
    <td><center>$pageurl</center></td>
    <td><center>$exposure</center></td>
    <td><center>$clicks</center></td>
    <td><center>$ctr</center></td>
  </tr>
}

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Replies are listed 'Best First'.
Re: illegal division by zero
by Caron (Friar) on Jan 30, 2004 at 08:29 UTC

    There are two reasons for that error:

    • You are splitting on "\|\|", but your string is separated by spaces. It should be split /\s+/,$db{$_}
    • You declared $exposure but you are using $exposures

    Are you using strict?

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Re: illegal division by zero
by PodMaster (Abbot) on Jan 30, 2004 at 08:26 UTC
    Perl's error messages are often very self explanatory, like in this case 
    E:\>perl
print 1/0;
Illegal division by zero at - line 1.

E:\>

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    You cannot divide numbers by 0 (or perl cannot natively). You should either ensure you're not dividing by zero, or use eval{} to trap any exceptions.

    MJD says "you can't just make shit up and expect the computer to know what you mean, retardo!"
    I run a Win32 PPM repository for perl 5.6.x and 5.8.x -- I take requests (README).
    ** The third rule of perl club is a statement of fact: pod is sexy.

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Re: illegal division by zero
by coec (Chaplain) on Jan 30, 2004 at 08:30 UTC
    In your my declaration, you have defined $exposure but you're trying to use $exposures later on (spot the plural). This is why use strict is IMHO mandatory.
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Re: illegal division by zero
by pelagic (Priest) on Jan 30, 2004 at 08:36 UTC
    Maybe you should do a proper debugging:
    use Data::Dumper;
print Dumper($db{$_});
my ($starttime, $filename, $pageurl, $exposure, $clicks) = split(/\|\|
+/, $db{$_});
print Dumper($starttime);
print Dumper($filename);
print Dumper($pageurl);
print Dumper($exposure);
print Dumper($clicks);

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    then you would exactli know, what the contents of your variables are ...
    Imre
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[d/l]
      Maybe you should do a proper debugging

      Or even better:

      print Data::Dumper->Dump([\%db, $starttime, $filename, $pageurl, 
        $exposure, $clicks],
        [qw(db starttime filename pageurl 
        exposure clicks)]);
__OUTPUT__

$db = {
    'key' => '6    fface.gif    http://www.go.com   19   8  4 '
      };
$starttime = '6';
$filename = 'fface.gif';
$pageurl = 'http://www.go.com';
$exposure = '19';
$clicks = '8';

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[d/l]
        THAT looks good, but consider answer fron Caron:
        you are using 
        $exposures
         ^

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        (plural) which is probably not defined.
        You should definitely use 
        use strict;

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