From: Pit Capitain <pit@...>
Date: 2005-01-30T20:07:48+09:00
Subject: Re: Array::uniq { block } ?

Trans schrieb:
> Has anyone, could anyone, write a Ruby version of this method? I'm not
> sure what its supposed to do exaclty. Id like to see source.

No problem:

   require 'set'

   class Array
     def uniq_by
       result = []
       values = Set.new
       each do |elem|
         value = yield elem
         unless values.include? value
           values << value
           result << elem
         end
       end
       result
     end
   end

   p ( 0 .. 9 ).to_a.uniq_by { |x| x % 4 }  # => [0, 1, 2, 3]

I bet Robert will transform this into a version using inject ;-)

Regards,
Pit