James Marks wrote:
>
> Down, near the bottom of this example code (marked), I'm trying to count
> the number of elements of an array which is the value of a key in a hash
> which is, itself, an element of an array. So far, I've been unsuccessful
> and I'm stumped as to what to try next.
>
> Help?
>
> my @web_sites_directory_tree =
>
> (
> {
> title => 'Web Site One',
> directory => 'web_site_one',
> subdirectory => [
> 'subdirectory_1',
> 'subdirectory_2',
> 'subdirectory_3',
> 'subdirectory_4',
> 'subdirectory_5',
> 'subdirectory_6'
> ]
> },
> {
> title => 'Web Site Two',
> directory => 'web_site_two',
> subdirectory => [
> 'subdirectory_1',
> 'subdirectory_2',
> 'subdirectory_3'
> ]
> },
> etc...
> )
>
> # COUNT NUMBER OF DIRECTORIES - (THIS WORKS)
> $directory_count = @web_sites_directory_tree;
>
> for (my $i = 0; $i < $directory_count; $i++) {
>
> my $title = "$web_sites_directory_tree[$i]{title}";
> my $directory = "$web_sites_directory_tree[$i]{directory}";
>
> # COUNT NUMBER OF SUBDIRECTORIES IN DIRECTORY $i - (THIS DOESN'T WORK)
> $subdirectory_count = $web_sites_directory_tree[$i]{subdirectory};
>
> # (CONSEQUENTLY, THE REST OF THIS FAILS)
> for (my $i = 0; $j < $subdirectory_count; $i++) {
>
> my $subdirectory = $web_sites_directory_tree[$i]{subdirectory}[$j];
>
> print "$title\n";
> print "$directory\n";
> print "$subdirectory\n";
>
> }
>
> }
>
> Thanks for any help you can provide.
Hi James
Apart from what Dermot was able to help you with, you'd be better off with a few
tweaks:
- Don't put quotes around scalar values, ie:
my $title = $web_sites_directory_tree[$i]{title};
my $directory = $web_sites_directory_tree[$i]{directory};
This often works, but is almost always unnnecessary. And it will fail altogether
if you are copying references (as you may have found out when trying to copy the
{subdirectory} element?)
- Avoid the C-style for loop construct. There's almost certainly a better way to
do it.
- Grab references to sub-elements out of the main structure to avoid repeating
the full key/index list each time.
Take a look at this. Doesn't it look better?
for my $i (0 .. $#web_sites_directory_tree) {
my $title = $web_sites_directory_tree[$i]{title};
my $directory = $web_sites_directory_tree[$i]{directory};
my $subdir_list = $web_sites_directory_tree[$i]{subdirectory};
for my $j (0 .. $#$subdir_list) {
my $subdirectory = $subdir_list->[$j];
print "$title\n";
print "$directory\n";
print "$subdirectory\n";
}
}
Cheers,
Rob
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
<http://learn.perl.org/> <http://learn.perl.org/first-response>
