Update array.rb

lib/core_extensions/array.rb

@@ -2,7 +2,7 @@ class Array
   def entropy
     each_with_object(Hash.new(0)) do |i, result|
       result[i] += 1
-    end.values.sum do |count|
+    end.values.inject(0, :+) do |count|
       percentage = count.to_f / length
 
       -percentage * Math.log2(percentage)