Urgent Help: Array of Hashes

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

Hi, I am new to perl and need your help on this problm: I have an Array of hashes which looks like this

$var = [
           {
             "D1" => 1,
             "D2" => 2
           },
           {
             "D2" => 5, 
             "D3" => 6 
           },
];
[download]

I need the sum of matching D's in both the arrays. Output should be a single associative array as shown below:

$var = 
           (
             "D1" => 1,
             "D2" => 7
             "D3" => 6 
           )
[download]

It would be great if the above array were sorted based on the values:

$var = 
           (
             "D2" => 7
             "D3" => 6 
             "D1" => 1,
           )
[download]

Kindly help. Rgds.

Comment on Urgent Help: Array of Hashes Select or Download Code

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Re: Urgent Help: Array of Hashes by ikegami (Patriarch) on Sep 26, 2007 at 23:45 UTC
`my $var = [ { "D1" => 1, "D2" => 2 }, { "D2" => 5, "D3" => 6 }, ]; my %combined; foreach my $subhash (@$var) { foreach my $key (keys %$subhash) { $combined{$key} += $subhash->{$key}; } } my @sorted_keys = sort { $combined{$b} <=> $combined{$a} } keys %combined; foreach my $key (@sorted_keys) { print("$key: $combined{$key}\n"); }` [download] You can't actually "sort the associative array", but you can control the order in which the data is accessed. That's what `@sorted_keys` is about.	[reply] [d/l] [select]
Re^2: Urgent Help: Array of Hashes by mirage_zz (Novice) on Sep 27, 2007 at 02:20 UTC
Hi, Thank you for the reply. Rgds	[reply]
Re: Urgent Help: Array of Hashes by merlyn (Sage) on Sep 26, 2007 at 23:39 UTC
It's odd that you used the word "associative array". Where did you get that from? That term has been disfavored for over a decade. Also, I smell homework. -- Randal L. Schwartz, Perl hacker	[reply]
Re^2: Urgent Help: Array of Hashes by mirage_zz (Novice) on Sep 26, 2007 at 23:47 UTC
Hi, I am building a small search utility, and the D's in the array are documents. The values are frequency of words in each document. The final array, just contains a summary of documents and the total occurences Rgds	[reply]
Re^3: Urgent Help: Array of Hashes by perlfan (Parson) on Sep 27, 2007 at 15:10 UTC
You can conveniently store the counts of particular "words" using a hash: `#!/usr/bin/env perl use strict; use warnings; my %freqs = (); # .... # for each match of $word $freqs{$word}++; # ... # the list the counts: foreach my $word (keys(%freqs)) { print "$word: $freqs{$word}\n"; } 1;` [download]	[reply] [d/l]