Advanced Search

Return to Snippet

Revision: 17804
at September 14, 2009 16:36 by deepsoul
Initial Code 
my @ary= qw( foo bar bla ack 42 foo );

my %set;
@set{@ary}= (1) x @ary;
# by the way: keys %set is now an array containing the elements
# of @ary without duplicates! (though possibly shuffled)

# or right during initialisation:
my %set2= map { $_ => 1; } @ary;
Initial URL 

                                

                                                            

                                    

                                        

                                        Initial Description
                                        

                                    

                                    
Perl hash sets are hashes used to represent sets.  Their keys are the set elements, and the corresponding values are just 1.  For keys that are not set elements, the hash will return undef, equivalent to false.

Adding a whole array to a hash set is often useful, but how to do it is slightly tricky and not widely known.  Here goes...

                                

                                                            

                                    

                                        

                                        Initial Title
                                        

                                    

                                    
Add array elements to hash set

                                

                                                            

                                    

                                        

                                        Initial Tags
                                        

                                    

                                    
list, array

                                

                                                            

                                    

                                        

                                        Initial Language
                                        

                                    

                                    
Perl