Perl Guru Forums: Perl Programming Help: Advanced: Multi-dimensional Hashes and value searches

CGI/Perl Guide | Learning Center | Forums | Advertise | Login

Site Search: in


	MAIN INDEX	SEARCH POSTS	WHO'S ONLINE	LOG IN

Home: Perl Programming Help: Advanced:
Multi-dimensional Hashes and value searches

Iconx
Novice

Apr 14, 2014, 2:40 PM

Post #1 of 4 (15147 views)

Multi-dimensional Hashes and value searches	Can't Post

I've messed around with this all kinds and read a few things but not even sure if this would work. Do I have to do a foreach/if/else?

Q: Is it possible to search a multi-dimensional hash for a value?

Overview:
I have a script that reads a directory and the contents of a each file in that directory, it then loads it into a hash that looks like this:

Code

%{ $record{$id_num} } = ( 
                filepath => $filepath 
                 uid           => $uid, 
                 acctname      => $acct_name, 
                 type          => $type, 
                 status       => $status, 
)

I intend to use this hash for a multiple different purposes one of which is to pull that accounts in a specific status. I know I could break it apart with a foreach and if/else to get status but isnt there a way to just make the hash print everything it has on an ID number for all status's having say a V? Hash looks like this in dumper:

Code

Print Dumper: 
$VAR1355 = '250198'; 
$VAR1356 = { 
             'status' => 'V', 
             'filepath' => '../records/active/250498.user73a', 
             'acctname' => 'user73a', 
              'type'          => 'Prod', 
             'uid' => '3001', 
             };

Question: So is it possible so find all entries in the hash that have a status V and be able to print everything that goes with that account?

PS - I know I can do something like this with the ID cause its the key like
print %{ $record{250198} }

I would have thought somehow chaining the hash like %{ $record{$id_num}{'v' } or something would produce this but I get why it doesnt, but I cant make status the key cause its not unique.

Make sense?

Thanks,
- Iconx

Iconx
Novice

Apr 14, 2014, 3:52 PM

Post #2 of 4 (15145 views)

Re: [Iconx] Multi-dimensional Hashes and value searches [In reply to]	Can't Post

FYI - this is supposed to be for a perl module.

What do you think?

I found in addition to making ${$record}{$id_num}, in the foreach loop of reading the file, I could do it like this and also make,

Code

%{$statuschk{$status}{$id_num} = (filepath=>$filepath,uid=>$uid.......etc)

and outside the foreach :

Code

my $value = 'V'; 
print $statuschk{$value};

shows me all the status's with V.

Is there a high cost to building multiple hashes on one read of a file? Is this the best way?

FishMonger
Veteran / Moderator

Apr 14, 2014, 4:32 PM

Post #3 of 4 (15144 views)

Re: [Iconx] Multi-dimensional Hashes and value searches [In reply to]	Can't Post

Quote

Q: Is it possible to search a multi-dimensional hash for a value?

Of course it's possible. It's also very easy.

Quote

Question: So is it possible so find all entries in the hash that have a status V and be able to print everything that goes with that account?

See the above answer.

Other than that, I can't figure out what you're tying to ask.

Your Dumper output tells me that you're not being consistent in how you're assigning the %record data. You should fix that issue before trying to write the code that outputs the data within the hash.

Laurent_R
Veteran / Moderator

Apr 15, 2014, 2:15 AM

Post #4 of 4 (15139 views)

Re: [Iconx] Multi-dimensional Hashes and value searches [In reply to]	Can't Post

It seems that you don't have a simple hash, but a hash of hashes (HoH). If you are unsure on how to use this type of structure, you probably need to read the perldsc document: http://perldoc.perl.org/perldsc.html.

Your need is not entirely clear to me, but you could try something like this:

Code

 
use strict; 
use warnings; 
 
my %outerhash = (  
    one => { 
   		"status" => "V",  
   		"filepath" => "../records/active/250498.user73a",  
   		"acctname" => "user73a",  
   		"type"          => "Prod",  
   		"uid" => "3001",  
    }, 
    two => {  
   		"status" => "X",  
   		"filepath" => "../records/active/250498.user73a",  
   		"acctname" => "user73a",  
   		"type"          => "Prod",  
   		"uid" => "3002",  
    }, 
    three => { 
   		"status" => "V",  
   		"filepath" => "../records/active/250498.user73a",  
   		"acctname" => "user73a",  
   		"type"          => "Prod",  
   		"uid" => "3003",  
    }, 
); 
foreach my $hashref (values %outerhash) { 
     next unless defined $hashref->{status}; 
     next if $hashref->{status} ne "V"; 
     print "\n"; 
     foreach my $key (keys %{$hashref}) { 
          print "$key => $hashref->{$key}\n"; 
     } 
}

This will print the following:

Code

acctname => user73a 
uid => 3003 
status => V 
type => Prod 
filepath => ../records/active/250498.user73a 
 
acctname => user73a 
uid => 3001 
status => V 
type => Prod 
filepath => ../records/active/250498.user73a

I hope this is more or less what you were looking for.

Search for (options)

Web Applications & Managed Hosting Powered by Gossamer Threads
Visit our Mailing List Archives