def test_compose_mapping_and_filter(self):
tdx = compose(
tdc.filtering(lambda x: x < 5),
tdc.mapping(lambda x: x * 2))
x = tdc.reduce(tdx(operator.mul),
range(1, 10), 1)
self.assertEqual(
x,
tdc.reduce(operator.mul,
(i * 2 for i in range(1, 10) if i < 5),
1))
def test_compose_three_transducers(self):
tdx = compose(
tdc.mapping(lambda x: x * 2),
tdc.mapping(lambda x: x * x),
tdc.filtering(lambda x: x % 2 == 0))
x = tdc.reduce(tdx(operator.add),
range(100), 0)
self.assertEqual(
x,
sum(filter(lambda x: x % 2 == 0,
(x * x
for x in (y * 2
for y in range(100))))))
def test_filtering(self):
f = tdc.filtering(lambda x: x < 10)
x = tdc.reduce(f(operator.add), range(100), 0)
self.assertEqual(x, sum(range(10)))
