Re: [htmltmpl] Nested loop puzzle - variable columns and rows

[Roger B. W. <ro...@fi...>]

On Wed, Feb 11, 2004 at 05:08:04AM -0800, LDT wrote:
>The question is:  how do I create my hash references to push into my loop in the correct order so that when I loop through my template, it all appears in the correct column?  I've been able to successfully loop through a structure that has fixed columns and fixed rows, but this one is puzzling me and I don't know where to start.

My approach would be to remodel the data into a fixed format, if there
are few enough data that you can get away with holding them in memory
twice (which for an HTML page you probably can). Also, while I used to
use the named hash variable method that's in the example (%r1, %r2,
etc.), these days I tend to use an explicitly anonymous hash because I
find it more intuitive.

So here's some (untested) code which should do what I think you want:

my %data;
my %account;
my %month;
# do database query here
while (my $account,$description,$month,$amount)=$sth->fetchrow_array) {
  $data{$account}{$month}=$amount;
  $account{$account}=$description;
  $month{$month}=1; # gives us a list of "active" months
}
my @months=sort {$a <=> $b} keys %month;
# or just my @months=(1..12); if you prefer
my @accounts=sort {$a <=> $b} keys %account;
my @ol;
foreach my $account (@accounts) {
  my @il;
  my $total=0;
  foreach my $month (@months) {
    # use an empty space if no data are available
    push @il,{amount => $data{$account}{$month} || ''};
    $total+=$data{$account}{$month};
  }
  push @ol,{account => $account,
            description => $account{$account},
            total => $total,
            month => \@il}
}
$tmpl->param(accounts => \@ol);

which would go with a template something like:

<tmpl_loop name=accounts>
<tr><td><tmpl_var name=account></td>
<td><tmpl_var name=description></td>
<tmpl_loop name=month>
<td>$<tmpl_var name=amount></td></tr>
</tmpl_loop>
<td>$<tmpl_var name=total></td></tr>
</tmpl_loop>

You'd generate the table headers separately (perhaps based on the
content of @months), and probably use sprintf() for formatting the
numbers, but I think that's the core of what you're after.

Hope this helps,

Roger