I think you need to use the syntax that forces types to arrays and hashes. It's in the Hashes of Arrays section of Chapter 9, Data Structures in the Camel book.

my %queries_by_key = (); # Hash of arrays

my $number_of_queries = scalar @all_queries;

for (my $i = 0 ; $i < $number_of_queries; ++$i) {
    my %query = %{ pop @all_queries }; # value of pop() is a hash

    foreach my $query_key (keys %query) {
        # Treat each value in %queries_by_key as an anonymous array
        push @{ $queries_by_key{$query_key} }, $query{$query_key};
    }
}

foreach my $key (sort keys %queries_by_key) {
     print "$key has ";
     print join ',', @{ $queries_by_key{$key} }; # treat as an array 
     print "\n";
}

[download]

I tried to make this clear, but the syntax is kinda confusing. Hopefully they'll explain it better in the book.

Hope this helps,

Chris

In reply to Re: 'group by query' from array of hashes by chayashida
in thread 'group by query' from array of hashes by bplegend

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