# File lib/core/facets/enumerable/occur.rb, line 16 def occur(n=nil) #:yield: result = Hash.new { |hash, key| hash[key] = Array.new } self.each do |item| key = item result[key] << item end if block_given? result.reject! { |key, values| ! yield(values.size) } else raise ArgumentError unless n if Range === n result.reject! { |key, values| ! n.include?(values.size) } else result.reject! { |key, values| values.size != n } end end return result.values.flatten.uniq end