def test_throws_error_if_conitinuous_atributes_are_present(self):
try:
path = datasetsDir(self) + 'numerical' + SEP + 'weather'
a,c = metadata(path)
dt = decisiontree.DecisionTree(training(path), a, c)
dt.train()
self.fail('should have thrown an error')
except inv.InvalidDataError:
pass
def test_maximum_gain_raito_stump_is_selected(self):
path = datasetsDir(self) + 'test_phones' + SEP + 'phoney'
_training = training(path)
a, c = metadata(path)
tree = decisiontree.DecisionTree(_training, a, c)
decision_stumps = tree.possible_decision_stumps([], _training)
max_gr_stump = tree.maximum_gain_ratio(decision_stumps)
self.assertEqual('pda', max_gr_stump.attribute.name)
def test_filter_does_not_affect_the_original_training(self):
path = datasetsDir(self) + 'minigolf' + SEP + 'weather'
a, c = metadata(path)
tree = decisiontree.DecisionTree(training(path), a, c)
tree.train()
outlook = tree.attributes[0]
self.assertEqual(9, len(tree.training))
filtered = tree.training.filter(outlook, 'sunny')
self.assertEqual(9, len(tree.training))
self.assertEqual(4, len(filtered))
def test_tree_creation(self):
path = datasetsDir(self) + 'test_phones' + SEP + 'phoney'
a, c = metadata(path)
tree = decisiontree.DecisionTree(training(path), a, c)
tree.train()
self.assertNotEqual(None, tree)
self.assertNotEqual(None, tree.root)
self.assertEqual('band', tree.root.attribute.name)
self.assertEqual(1, len(tree.root.children))
self.assertEqual('size', tree.root.children['tri'].attribute.name)
def test_ignores_selected_attributes_in_next_recursive_iteration(self):
path = datasetsDir(self) + 'minigolf' + SEP + 'weather'
a, c = metadata(path)
tree = decisiontree.DecisionTree(training(path), a, c)
tree.train()
self.assertEqual('outlook', tree.root.attribute.name)
children = tree.root.children
self.assertEqual(2, len(children))
sunny = children['sunny']
self.assertEqual('temperature', sunny.attribute.name)
self.assertEqual(0, len(sunny.children))
rainy = children['rainy']
self.assertEqual('windy', rainy.attribute.name)
self.assertEqual(0, len(rainy.children))