Storing a Hash Made of Two Arrays in Another Hash

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

Howdy Monks,

So I've been bejiggering with this code for awhile and it's not working out the way I need it to. I am parsing a text file where the first line consists of headings that I would like to use for keys in a hash. The next few lines contain values. I'd like to store each line of values in a hash that is keyed by the headings in the first line, and contains the values in the second line. However, I'd like to store each of those hashes in a master hash that is keyed by the first value in each row. So the data I am looking at resembles the following:

Heading 1    Heading 2    Heading 3  ...
Value A1     Value A2     Value A3   ...
Value B1     Value B2     Value B3   ...
.
.
.
[download]

I am trying to parse that code with the following subroutine (please note values are delimited by tabs, so the parsing is working as expected)

sub get_fields{
    my $local_filein = shift;    # Input file needs to be the first fi
+le passed to get_fields
    
    my %tmp_hash;
    my %tickets;
    my @keys;
    my @values;
    
    while(my $line = <$local_filein>){
        chomp $line;
        
        if ($line =~ m/^\D/){
            @keys = split(/\t/, $line);
        }elsif($line =~ m/d/){
            @values = split(/\t/, $line);
            @tmp_hash{@keys} = @values;
            
            # foreach(keys %tmp_hash){
            #     print "KEY: $_ VALUE: $tmp_hash{$_}\n"
            # }
            
            $tickets { $values[0] } = %tmp_hash;
            
            #$tickets{ @values[0]{@keys}}  = @values;
            #$tickets{ $values[0] } = { each %tmp_hash };  # Each is a
+ piece of shit. Use @ context or something else.
        }
    }
    
    #@tickets{@keys} = @values;
    
    return %tickets;
}
[download]

The line of code I am having trouble with is the one where I am trying to assign the values of %tmp_hash into the master hash %tickets. As you can see, I've tried a few different things which I've commented out. Basically, %tmp_hash is getting created just fine by assigning it the arrays @keys and @values. But I'd like to do something similar to make %tickets the hash of temporary hashes keyed by the first value in the @values array. I can't seem to get the context to work out.

Any help y'all could provide would be appreciated.

Thanks!
Brady

Comment on Storing a Hash Made of Two Arrays in Another Hash Select or Download Code

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Re: Storing a Hash Made of Two Arrays in Another Hash by tobyink (Canon) on Jan 10, 2012 at 18:01 UTC
Something like this? `use Modern::Perl; use Data::Dumper; my @field_names; my %master_hash; while (<DATA>) { chomp; if (1..1) { @field_names = split /\t/ and next; } my %this_hash; my @values = split /\t/; @this_hash{ @field_names } = @values; $master_hash{$values[0]} = \%this_hash; } print Dumper \%master_hash; __DATA__ Name Pet monkey John Biggles Steve Bubbles Henry Binky` [download] In your particular example, this line is wrong: `$tickets { $values[0] } = %tmp_hash;` You're trying to assign a hash into a scalar slot. You need to assign a reference to the hash instead: `$tickets { $values[0] } = \%tmp_hash;` See perldoc perlref and perldoc perllol.	[reply] [d/l] [select]
Re^2: Storing a Hash Made of Two Arrays in Another Hash by BJ_Covert_Action (Beadle) on Jan 10, 2012 at 18:51 UTC
Perfect! Worked like a charm. Thanks toby! I knew it was something simple, but it's been awhile since I built complex data structures in perl and I'm dusting off the cobwebs still.	[reply]
Re^2: Storing a Hash Made of Two Arrays in Another Hash by BJ_Covert_Action (Beadle) on Jan 10, 2012 at 18:10 UTC
Yeah, I knew which line was wrong. I didn't know how to make that line right. Let me try the reference. Thanks!	[reply]
Re: Storing a Hash Made of Two Arrays in Another Hash by toolic (Bishop) on Jan 10, 2012 at 17:59 UTC
if ($line =~ m/^\D/){ That matches every line of the input you have shown. The `elsif` clause is never entered. Therefore, we can not reproduce your results with your input data and code. See http://sscce.org.	[reply] [d/l]
Re^2: Storing a Hash Made of Two Arrays in Another Hash by BJ_Covert_Action (Beadle) on Jan 10, 2012 at 18:07 UTC
Yeah, the sample input I was giving was just a template. Here, try this: `Heading1 Heading2 Heading3 100 200 300 400 500 600` [download] You're still going to have to replace those spaces with tab characters to make the parsing work on that though.	[reply] [d/l]