# File lib/core/facets/array/occur.rb, line 18 def occur(n=nil) #:yield: h = Hash.new(0) each do |i| h[i] += 1 end case n when nil h.delete_if{ |_,v| ! yield(v) }.keys when Range h.delete_if{ |_,v| ! n.include?(v) }.keys else h.delete_if{|_,v| v != n}.keys end end