Added doctest to decision_tree.py

machine_learning/decision_tree.py

@@ -49,6 +49,26 @@ def train(self, x, y):
         The contents of y are the labels for the corresponding X values
 
         train does not have a return value
+
+        Examples:
+        1. Try to train when x & y are of same length & 1 dimensions (No errors)
+        >>> dt = DecisionTree()
+        >>> dt.train(np.array([10,20,30,40,50]),np.array([0,0,0,1,1]))
+
+        2. Try to train when x is 2 dimensions
+        >>> dt = DecisionTree()
+        >>> dt.train(np.array([[1,2,3,4,5],[1,2,3,4,5]]),np.array([0,0,0,1,1]))
+        Error: Input data set must be one dimensional
+
+        3. Try to train when x and y are not of same length
+        >>> dt = DecisionTree()
+        >>> dt.train(np.array([1,2,3,4,5]),np.array([[0,0,0,1,1],[0,0,0,1,1]]))
+        Error: X and y have different lengths
+
+        4. Try to train when x & y are of same length but diffetent dimensions
+        >>> dt = DecisionTree()
+        >>> dt.train(np.array([1,2,3,4,5]),np.array([[1],[2],[3],[4],[5]]))
+        Error: Data set labels must be one dimensional
         """
 
         """