map to hash of arrays

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

I have data returned from a sql query that comes as:

Row 1
   label1 : item1
   label2 : item1
Row 2
   label1 : item2
   label2 : item2
[download]

I need all of the information after the colons. The odd numbered values (label1) I want to use as a hash key and the even numbered values (label2) I want to use as the hash value. I've gotten that far with the following: my %hash = map { m!(?:\S+) : (\S+)! } @stuff_from_query;. The problem I've encountered is that the data after label1 could be duplicate, but with different values for label2. The current code stores only one value, overwritting the previous. I need to somehow incorporate a push so that the value of the hash is an anonymous array, containing all found label2 values.

Is there a nifty way I can still incorporate this into a map line?

Comment on map to hash of arrays Select or Download Code

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Re: map to hash of arrays by ccn (Vicar) on Jul 22, 2004 at 21:03 UTC
Is it what you want? `use Data::Dumper; my $data = <<EOT; Row 1 label1 : item1 label2 : item1 Row 2 label1 : item2 label2 : item2 EOT push @{$hash{$1}}, $2 while $data =~ /(\S+)\s:\s(\S+)/g; print Dumper(\%hash);` [download] `$VAR1 = { 'label1' => [ 'item1', 'item2' ], 'label2' => [ 'item1', 'item2' ] };` [download]	[reply] [d/l] [select]
Re^2: map to hash of arrays by emilford (Friar) on Jul 26, 2004 at 14:12 UTC
Not exactly. Let me try my explanation again. Here is a chunk of sample data to illustrate what I'd like to do. `Row 17 object_label : yang object_id : 123456 Row 18 object_label : yang object_id : 789101112 Row 19 object_label : yang object_id : 13141516171819` [download] The data comes in exactly like that, line by line. I need to ignore the Row \d+ lines and grab the rest of the information, so that I end up with a hash of arrays where 'object_label' are used as keys and 'object_id' with the same 'object_label' are items in an array. `%hash = { 'yang' => [ '123456', '789101112', '13141516171819' ] }` [download]	[reply] [d/l] [select]
Re^3: map to hash of arrays by ccn (Vicar) on Jul 26, 2004 at 14:26 UTC
please try this: `push @{$hash{$1}}, $2 while $data =~ /object_label\s+:\s+(\S+)[^:]+:\s+(\S+)/g;`	[reply] [d/l]
Re^4: map to hash of arrays by emilford (Friar) on Jul 27, 2004 at 13:51 UTC
Re: map to hash of arrays by rnahi (Curate) on Jul 22, 2004 at 21:26 UTC
Perhaps DBI Recipes has something useful for you. Check the sections about lists of hashes and hashes of hashes.	[reply]
Re: map to hash of arrays by dpuu (Chaplain) on Jul 22, 2004 at 21:13 UTC
It is obviously possible, but it would not be "nifty". In fact, I think it'd be worse solution than just using a C<for> loop in the first place. You just have to build a temportary hash off to the side. But if you're going to build a tmp hash, then you might as well just build the real one. --Dave Opinions my own; statements of fact may be in error.	[reply]
Re^2: map to hash of arrays by emilford (Friar) on Jul 26, 2004 at 14:18 UTC
That's my issue. I want to build the real hash of arrays without the need of a temporary one. I'm just not sure how to go about doing that.	[reply]
Re^3: map to hash of arrays by dpuu (Chaplain) on Jul 26, 2004 at 15:22 UTC
Use a while loop, not a map: `my %hash; my $key; while (<>) { /\S+ : (\S+)/ or die "unexpected line format: $_"; my $value = $1; if (defined $key) { push @{ $hash{$key} }, $value; undef $key; else { $key = $value; } }` [download] --Dave Opinions my own; statements of fact may be in error.	[reply] [d/l]
Re^4: map to hash of arrays by emilford (Friar) on Jul 27, 2004 at 13:53 UTC
Re^5: map to hash of arrays by dpuu (Chaplain) on Jul 27, 2004 at 16:26 UTC
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