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Re^5: Hash of Hashes from file

by Cristoforo (Deacon)
on Apr 03, 2012 at 20:57 UTC ( #963314=note: print w/ replies, xml ) Need Help??


in reply to Re^4: Hash of Hashes from file
in thread Hash of Hashes from file

Yes, it should be possible but the syntax might get sticky. As scorpio17 says in this thread, what you want to do with the data is one the the deciding factors in how you want to store it. (Along with other factors). If the data is too large to load into memory, you may need to consider some of the suggestions offered by others here.

If the requirement is just to produce output like you provided, a Hash of Hashes may be a good choice.

#!/usr/bin/perl use strict; use warnings; my %data; while (<DATA>) { my ($user, $site, $cat) = /"([^"]+)"/g; $data{$user}{$site} = $cat; } for my $user (keys %data) { my $href = $data{$user}; print $user, "\n"; print "\tWebsite: $_, Category: $href->{$_}\n" for keys %$href; } __DATA__ user="john" website="www.yahoo.com" type="Entertainment" user="david" website="www.facebook.com" type="Social Networking" user="john" website="www.facebook.com" type="Social Networking" user="mike" website="www.google.com" type="Search Engines"
Output was:
john Website: www.yahoo.com, Category: Entertainment Website: www.facebook.com, Category: Social Networking mike Website: www.google.com, Category: Search Engines david Website: www.facebook.com, Category: Social Networking
Update: With a file this large, would it be likely for one user to visit the same website more than once?


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Re^6: Hash of Hashes from file
by cipher (Acolyte) on Apr 05, 2012 at 01:12 UTC
    Yes users visit same websites multiple times. For this reason I added Key as string "Website" and value as the actual website.
      I got the following output:
      C:\Old_Data\perlp>perl t33.pl david Website: www.facebook.com, Category: Social Networking john Website: www.yahoo.com, Category: Entertainment Website: www.yahoo.com, Category: Entertainment Website: www.yahoo.com, Category: Entertainment Website: www.facebook.com, Category: Social Networking mike Website: www.google.com, Category: Search Engines Name: john Website Count www.yahoo.com 3 www.facebook.com 1 Type Count Entertainment 3 Social Networking 1 Name: mike Website Count www.google.com 1 Type Count Search Engines 1 Name: david Website Count www.facebook.com 1 Type Count Social Networking 1
      From this data:
      user="john" website="www.yahoo.com" type="Entertainment" user="john" website="www.yahoo.com" type="Entertainment" user="john" website="www.yahoo.com" type="Entertainment" user="david" website="www.facebook.com" type="Social Networking" user="john" website="www.facebook.com" type="Social Networking" user="mike" website="www.google.com" type="Search Engines"
      Notice that there are quotes surrounding every field. The regular expression that captures these fields from the file would need to be changed if thats not the case.

      In my program I use 2 hashes - one to count the number of sites visited by each user, %count, and one to count each address and category (by user), %data. It seems to work OK for this small data set.

      #!/usr/bin/perl use strict; use warnings; my (%data, %count); while (<DATA>) { my ($user, $site, $cat) = /"([^"]+)"/g; $data{$user}{ qq{$site$;$cat} }++; $count{$user}++; } for my $user (sort keys %data) { my $href = $data{$user}; print $user, "\n"; for my $key (keys %$href) { my $str = sprintf "\tWebsite: %s, Category: %s\n", split /$;/, + $key; print $str x $href->{$key}; } } my @ordered = sort {$count{$b} <=> $count{$a}} keys %count; print "\n\n"; for my $user (@ordered) { my $href = $data{$user}; print "Name: $user\n\tWebsite Count\n"; for my $key (sort {$href->{$b} <=> $href->{$a}} keys %$href) { printf "\t%-20s%d\n", (split /$;/, $key)[0], $href->{$key}; } print "\n"; print "\tType Count\n"; for my $key (sort {$href->{$b} <=> $href->{$a}} keys %$href) { printf "\t%-20s%d\n", (split /$;/, $key)[1], $href->{$key}; } print "\n\n"; }
      The line $data{$user}{ qq{$site$;$cat} }++;
      uses a 'compound' key ($site and $cat joined by $;).

      Here is a dump of %data.

      $VAR1 = { 'john' => { 'www.yahoo.com‡˜Entertainment' => 3, 'www.facebook.com‡˜Social Networking' => 1 }, 'mike' => { 'www.google.com‡˜Search Engines' => 1 }, 'david' => { 'www.facebook.com‡˜Social Networking' => } };

      Update: Whoops, that doesn't count the categories correctly :-(
      If there was another site with the same category, it wouldn't be totaled with the same category from another site.

        Think I got it this time! I used the data structure that scorpio17 used (I printed out the dump here also). Output:
        C:\Old_Data\perlp>perl t33.pl $VAR1 = { 'john' => { 'site' => [ 'www.yahoo.com', 'www.yahoo.com', 'www.yahoo.com', 'www.facebook.com' ], 'type' => [ 'Entertainment', 'Entertainment', 'Entertainment', 'Social Networking' ] }, 'mike' => { 'site' => [ 'www.google.com' ], 'type' => [ 'Search Engines' ] }, 'david' => { 'site' => [ 'www.facebook.com' ], 'type' => [ 'Social Networking' ] } }; david Website: www.facebook.com, Category: Social Networking john Website: www.yahoo.com, Category: Entertainment Website: www.yahoo.com, Category: Entertainment Website: www.yahoo.com, Category: Entertainment Website: www.facebook.com, Category: Social Networking mike Website: www.google.com, Category: Search Engines Name: john Website Count www.yahoo.com 3 www.facebook.com 1 Type Count Entertainment 3 Social Networking 1 Name: mike Website Count www.google.com 1 Type Count Search Engines 1 Name: david Website Count www.facebook.com 1 Type Count Social Networking 1 C:\Old_Data\perlp>
        And here is the code:
        #!/usr/bin/perl use strict; use warnings; my %data; while (<DATA>) { my ($user, $site, $cat) = /"([^"]+)"/g; push @{ $data{$user}{site} }, $site; push @{ $data{$user}{type} }, $cat; } for my $user (sort keys %data) { my $site_ary = $data{$user}{site}; my $type_ary = $data{$user}{type}; print $user, "\n"; for my $i (0 .. $#$site_ary) { printf "\tWebsite: %s, Category: %s\n", $site_ary->[$i], $type +_ary->[$i]; } } print "\n\n"; for my $user (sort by_count_desc keys %data) { my $site_ary = $data{$user}{site}; my $type_ary = $data{$user}{type}; my (%site_cnt, %type_cnt); $site_cnt{$_}++ for @$site_ary; $type_cnt{$_}++ for @$type_ary; print "Name: $user\n\tWebsite Count\n"; for my $site (sort {$site_cnt{$b} <=> $site_cnt{$a}} keys %site_cn +t) { printf "\t%-20s%d\n", $site, $site_cnt{$site}; } print "\n"; print "\tType Count\n"; for my $type (sort {$type_cnt{$b} <=> $type_cnt{$a}} keys %type_cn +t) { printf "\t%-20s%d\n", $type, $type_cnt{$type}; } print "\n\n"; } sub by_count_desc { @{$data{$b}{site}} <=> @{$data{$a}{site}}; } __DATA__ user="john" website="www.yahoo.com" type="Entertainment" user="john" website="www.yahoo.com" type="Entertainment" user="john" website="www.yahoo.com" type="Entertainment" user="david" website="www.facebook.com" type="Social Networking" user="john" website="www.facebook.com" type="Social Networking" user="mike" website="www.google.com" type="Search Engines"
        Hope this helps, Chris

        Update: Added sub by_count_desc.

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