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How to create nesting hashes given the innermost value and an array of keys?

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Contributed by EchoAngel on Mar 03, 2005 at 16:33 UTC
Q&A  > hashes


Description:

E.g. given the array @a = qw/foo bar burp/ and the value 1, create a hash like
%h = ( 'foo' => { 'bar' => { 'burp' => 1 } } );

Answer: How to create nesting hashes given the innermost value and an array of keys?
contributed by Roy Johnson

Recursively walk a hash to get to an element

Answer: How to create nesting hashes given the innermost value and an array of keys?
contributed by niggles

Input in @a, output in $last[-1].

use Data::Dumper; $Data::Dumper::Deepcopy = 1; my @a = qw/foo bar baz/; my @last = (1); push @last, { $_ => $last[-1] } foreach reverse @a; print Dumper( $last[-1] ); # result
I use Data::Dumper just to print the output. It is not required to obtain the result. Output:
$VAR1 = { 'foo' => { 'bar' => { 'baz' => 1 } } };
Answer: How to create nesting hashes given the innermost value and an array of keys?
contributed by EchoAngel

This functiontakes elements in an array and builds them into keys for a hash:

# Usage: UsesArrayElementsAsKeyElementsInHash( \%hash, $value, @array + ) use Carp; sub UsesArrayElementsAsKeyElementsInHash { my $hash = my $root = ( ref $_[0] ? shift : {} ); my $value = shift; my $last = pop; for my $key ( @_ ) { $hash = ( $hash->{$key} ||= {} ); ref $hash or croak "key = $key\n"; } $hash->{$last} = $value; return $root; }

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