Please could somebody put the following line into English. 
next if $seen{ $elem }++;

[download]
in the code: 
 my %hash   = map { $_, 1 } @array;

 # or a hash slice: @hash{ @array } = ();
 # or a foreach: $hash{$_} = 1 foreach ( @array );
  
 my @unique = keys %hash;
  
 my @unique = ();
 my %seen   = ();
  
 foreach my $elem ( @array )
   {
     next if $seen{ $elem }++;
     push @unique, $elem;
   }

[download]
My attempt is:

Insert $elem into the hash 'seen' and skip to the next loop event if this $elem is already present in the hash 'seen'.

I realise that my attempt is not quite there.

In reply to What does 'next if $hash{$elem}++;' mean? by Win

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