Avoid polluting namespace

lib/refinements/array_classification.rb

@@ -0,0 +1,7 @@
+module ArrayClassification
+  refine Array do
+    def classification
+      collect(&:last)
+    end
+  end
+end

lib/refinements/array_entropy.rb

@@ -0,0 +1,13 @@
+module ArrayEntropy
+  refine Array do
+    def entropy
+      each_with_object(Hash.new(0)) do |i, result|
+        result[i] += 1
+      end.values.inject(0, :+) do |count|
+        percentage = count.to_f / length
+
+        -percentage * Math.log2(percentage)
+      end
+    end
+  end
+end

lib/refinements/object_persistence.rb

@@ -0,0 +1,11 @@
+module ObjectPersistence
+  refine Object do
+    def save_to_file(filename)
+      File.open(filename, "w+") { |f| f << Marshal.dump(self) }
+    end
+
+    def self.load_from_file(filename)
+      Marshal.load(File.read(filename))
+    end
+  end
+end