Perl Hashes / Accessing data

chtaylo2 has asked for the wisdom of the Perl Monks concerning the following question:

Hi! I have the following hash being created. I'm looping through various $sub_alias and $topic_sub so I know the value of those. My question is how do I access the value of $id and the URL / TITLE etc...

$data{$sub_alias}{$topic_sub}{$id}{ 'URL' } = 'my_url';
$data{$sub_alias}{$topic_sub}{$id}{ 'TITLE' } = 'mytitle';
$data{$sub_alias}{$topic_sub}{$id}{ 'CONTENTTYPE' } = 'my_type';
$data{$sub_alias}{$topic_sub}{$id}{ 'SUBCATEGORY' } = 'my_sub';
$data{$sub_alias}{$topic_sub}{$id}{ 'TOPIC_DESCRIPTION' } = 'my_desc';
$data{$sub_alias}{$topic_sub}{$id}{ 'RELATED_TOPICS' } = 'my topic';
[download]

Something like this maybe?

foreach $tmp_sa (@foo)  {

   foreach $t (@bar)..... {

      foreach ( keys %{$data->{$tmp_sa}{$t}} ) {
         print "$data->{$tmp_sa}{$t}{$_}{'URL'}\n";
      } 

   }

}
[download]

Thank you!

Comment on Perl Hashes / Accessing data Select or Download Code

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Re: Perl Hashes / Accessing data by locked_user sundialsvc4 (Abbot) on Jul 30, 2010 at 00:06 UTC
Another nifty trick is to use the `each()` function, which iterates directly over the keys in a hash without making a separate copy. May not be applicable in your case, but always worth noting. (It once made a huge difference in a program that was working with a “hash” that was actually `tie`d to a massive Berkeley-DB file...)
Re^2: Perl Hashes / Accessing data by chtaylo2 (Initiate) on Jul 30, 2010 at 02:13 UTC
Thank you both. Worked great!	[reply]
Re: Perl Hashes / Accessing data by morgon (Priest) on Jul 29, 2010 at 23:02 UTC
`$data{$sub_alias}{$topic_sub}{$id}{ 'URL' } = 'my_url';` [download] creates a %data-hash (not a $data reference to a hash - I hope you know what I mean). So do get to get to the $id-values you do need to get rid of the "->": `foreach $tmp_sa (@foo) { foreach $t (@bar)..... { foreach ( keys %{$data{$tmp_sa}{$t}} ) { print "$data{$tmp_sa}{$t}{$_}{'URL'}\n"; } }` [download]	[reply] [d/l] [select]