Hash with three keys

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

I have an issue that I need to loop over a hash that has three keys. I have written code to loop over two keys before but for some reason I am struggling with this task. Example of code used to loop over two key hash

foreach my $key1 (sort keys %hash){
    foreach my $key2 (sort keys %{$hash{$key1}}){
        print "$key1\t$key2\t$hash{$key1}{$key2}\n";
    }
}
[download]

I really think the three key structure is best for this task as I have a very complicated structure.

foreach my $key1 (sort keys %hash){    
    foreach my $key2 (sort keys %{$hash{$key1}} ){
        foreach my $key3 (sort keys  %{$hash{$hash{$key1}} }       ){
            print OFH "$key1\t$key2\t$key3\t$hash{$key1}{$key2}{$key3}
+\n";
        }
    }
}
[download]

Thanks

Comment on Hash with three keys Select or Download Code

Replies are listed 'Best First'.
Re: Hash with three keys by AnomalousMonk (Archbishop) on Dec 12, 2013 at 21:15 UTC
`foreach my $key3 (sort keys %{$hash{$hash{$key1}} } ){ ... }` This may serve you better (untested): `foreach my $key3 (sort keys %{ $hash{$key1}{$key2} }) { ... }` Also note that with Perl version 5.14+, keys et al will take a hash reference directly: see `keys EXPR`	[reply] [d/l] [select]
Re^2: Hash with three keys by Jeri (Scribe) on Dec 12, 2013 at 21:18 UTC
thanks everyone. got it working :)	[reply]
Re: Hash with three keys by hdb (Monsignor) on Dec 12, 2013 at 21:46 UTC
Recursion is another solution to this, especially if you do not know upfront how deep your hashes are nested or if the depth is not the same everywhere: `use strict; use warnings; sub loop_over_hash { my( $keys, $href ) = @_; print join( ',', @$keys , $href ), "\n" and return unless 'HASH' e +q ref $href; loop_over_hash( [ @$keys, $_ ], $href->{$_} ) for keys %$href; } my %hash = ( a => { 1 => { x => 5, y => 6 }, 2 => { s => 7, t => 8 } }, b => { 3 => 'end', }, ); loop_over_hash [], \%hash;` [download]	[reply] [d/l]
Re: Hash with three keys by toolic (Bishop) on Dec 12, 2013 at 21:07 UTC
perldsc	[reply]


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