Sorting a HoH by values of the nested hashes

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

Dear Monks, I have a data structure like this:

$VAR1 = {
          '1.2.3.4' => {
                              '27029' => 5,
                              '20617' => 1                            
+                                                                
                       },                                             
+                                                           
          '1.2.3.5' => {                                              
+                                                          
                              '51509' => 1,                           
+                                                               
                              '17427' => 1,                           
+                                                               
                              '63961' => 7,                           
+                                                               
                              '22331' => 1,                           
+                                                               
                              '20780' => 7                            
+                                                               
                       },                                             
+                                                          
          '1.2.3.6' => {                                              
+                                                        
                              '1500' => 3                             
+                                                             
                       },                                             
+                                                        
};
[download]

It's a HoH where nested keys are ports and values are number of connections to that port. I'm printing out the data like this:

for my $ip ( keys %conn ) { 
    for my $port ( keys $conn{$ip} ) { 
        if ( $conn{$ip}{$port} > $max_conns ) { 
            printf "%-15s connected to TCP port %5d %9d times\n", $ip,
+ $port,
              $conn{$ip}{$port};
        }   
    }   
}
[download]

I'd like to sort the output based on the number of connections to a port, ex.:

1.2.3.5         connected to TCP port    20780     7 times
1.2.3.4         connected to TCP port    27029     5 times
1.2.3.6         connected to TCP port     1500     3 times
...
[download]

How do I write a sort like this? (You can find the whole script here.)

Well done is better than well said. -- Benjamin Franklin

Comment on Sorting a HoH by values of the nested hashes Select or Download Code

Replies are listed 'Best First'.
Re: Sorting a HoH by values of the nested hashes by hdb (Monsignor) on Nov 20, 2013 at 12:42 UTC
I cannot see any other way than to first flatten the structure (like Anonymonk before me) and then to sort and print: `printf "%-15s connected to TCP port %5d %9d times\n", @$_ for sort { $b->[2] <=> $a->[2] } grep { $_->[2] > $max_conns } map { my $ip = $_; map { [ $ip, $_, $conn{$ip}{$_} ] } keys %{$con +n{$ip}} } keys %conn;` [download] Update: Added the grep-line to incorporate the check as in OP.	[reply] [d/l]
Re: Sorting a HoH by values of the nested hashes by Anonymous Monk on Nov 20, 2013 at 12:34 UTC
http://learn.perl.org/faq/perlfaq4.html#How-do-I-sort-an-array-by-anything-, http://perldoc.perl.org/perlfaq4.html#How-do-I-sort-an-array-by-%28anything%29%3f `push @entries, [ $sprintfed, $conn{$ip}{$port} ]; @entries = sort { $$a[1] <=> $$b[1] } @entries; @entries = map { $$_[0] } @entries; print @entries;` [download] Understanding the Schwartzian transform.	[reply] [d/l]
Re: Sorting a HoH by values of the nested hashes by Laurent_R (Canon) on Nov 20, 2013 at 13:29 UTC
Hi There must be a better way, but this the best idea I could come up quickly from the top of my mind, and it works: `use strict; use warnings; my @array; my $VAR1 = { '1.2.3.4' => { '27029' => 5, '20617' => 1 }, '1.2.3.5' => { '51509' => 1, '17427' => 1, '63961' => 7, '22331' => 1, '20780' => 7 }, '1.2.3.6' => { '1500' => 3 }, + }; for my $var1 (keys %$VAR1) { push @array, [$var1, $_, $$VAR1{$var1}{$_}] for keys %{$$VAR1{$var +1}}; } print map {$_->[0], "\t", $_->[1], "\t", $_->[2], "times \n"} sort {$a +->[2] <=> $b->[2]} @array;` [download] Output: `1.2.3.5 51509 1times 1.2.3.5 17427 1times 1.2.3.5 22331 1times 1.2.3.4 20617 1times 1.2.3.6 1500 3times 1.2.3.4 27029 5times 1.2.3.5 63961 7times 1.2.3.5 20780 7times` [download] Update This is strange, there was no answer when I posted my answer, and now it appears that two monks actually posted before me. I do not understand this and would probably have not posted the above if I has seen the prevoous answers.	[reply] [d/l] [select]
Re: Sorting a HoH by values of the nested hashes by Random_Walk (Prior) on Nov 20, 2013 at 23:06 UTC
Fun with maps `use strict; use warnings; use 5.010; use Data::Dumper; # ip => port => count my $d = { '1.2.3.4' => { '427029' => 41, '420617' => 42, }, '1.2.3.5' => { '551509' => 51, '517427' => 52, }, '1.2.3.6' => { '671500' => 61, '622331' => 62, }, }; my $ip; say for sort map { $ip = $_;map { sprintf "%04d connections %s -> %s", $d->{$ip}->{$_}, $ip, $_ } keys %{$d->{$ip}} } keys %$d;` [download] Cheers, R. Pereant, qui ante nos nostra dixerunt!	[reply] [d/l]