From perlfunc on the values function:

The values are returned in an apparently random order. The actual random order is subject to change in future versions of perl, but it is guaranteed to be the same order as either the keys or each function would produce on the same (unmodified) hash.

I think this means that I can (safely) do the following to build a new hash where the key/value pairs have switched roles (ie. for each pair, the new hash uses the value as key, and the key as value):

use Data::Dump qw( dump );

my %hash = ( 1 => "Piker", 2 => "Vin", 3 => "Sang" );
my %revhash;
@revhash{ values %hash } = keys %hash;

print dump( \%hash ), "\n";
print dump( \%revhash ), "\n";

[download]

Have I missed something regarding the hash iterators, or is this an acceptable way of doing things? I am well aware of other solutions to this problem using loops and map, but I'm curious and trying to learn something on slices.

pernod
--
Mischief. Mayhem. Soap.

In reply to Swapping keys and values in a hash with slices by pernod

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