In this: 

my %hash = (
   a => [ '1','2', ],
   b => [ '2','3', ],
   c => [ '1','2', ],
);

[download]
are a and c pointing to the same array ref or are they two different arrays just happening to have the same content? This might change the best strategy to remove the duplicates.

Generally, the best way to remove duplicates is to use a hash. So in this case you have to construct the reverse hash to identify the keys of the original hash that you want to keep. And the best way to do this will depend on the anwer to my first question above.

In reply to Re: Removing duplicate values for a hash of arrays by Laurent_R
in thread Removing duplicate values for a hash of arrays by perlvroom

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