Sets in Ruby?

Question

I need a collection that is like a set. Basically I'm scanning a long string and adding words to the collection but I want to be able to detect when there are duplicates.

If sets aren't available, what's the most efficient way of doing this in Ruby? Brownie points for example code.

Answer 1

There is a Set class in ruby. You can use it like so:

require 'set'  set = Set.new  string = "a very very long string"  string.scan(/\w+/).each do |word|   unless set.add?( word )     # logic here for the duplicates   end end 

Although, I'm wondering if you would want to count the instances in that case the following example would be better:

instances = Hash.new { |h, k| h[k] = 0 }  string.scan(/\w+/).each do |word|   instances[word] += 1 end 

Answer 2

From the documentation:

a = [ "a", "a", "b", "b", "c" ] a.uniq  #gets you   ["a", "b", "c"] a.uniq.uniq! #gets you nil (no duplicates :)