def test_bad_args2():
assert_value_error(lambda: kfold(nrows=-1, nsplits=1),
"Argument `nrows` in kfold() cannot be negative")
assert_value_error(lambda: kfold(nrows=3, nsplits=-3),
"Argument `nsplits` in kfold() cannot be negative")
assert_value_error(lambda: kfold(nrows=5, nsplits=0),
"The number of splits cannot be less than two")
assert_value_error(lambda: kfold(nrows=1, nsplits=2),
"The number of splits cannot exceed the number of rows")
def test_kfold_k_2(seed):
random.seed(seed)
n = 2 + int(random.expovariate(0.01))
h = n // 2
splits = kfold(nrows=n, nsplits=2)
assert splits == [(range(h, n), range(0, h)),
(range(0, h), range(h, n))]
def test_kfold_k_3(seed):
random.seed(seed)
n = 3 + int(random.expovariate(0.01))
h1 = n // 3
h2 = 2 * n // 3
splits = kfold(nrows=n, nsplits=3)
assert len(splits) == 3
assert splits[0] == (range(h1, n), range(0, h1))
assert splits[1][1] == range(h1, h2)
assert splits[2] == (range(0, h2), range(h2, n))
assert isinstance(splits[1][0], dt.Frame)
assert splits[1][0].nrows == h1 + n - h2
assert splits[1][0].to_list()[0] == list(range(0, h1)) + list(range(h2, n))
def test_bad_args2():
msg = r"Argument nrows in function datatable.kfold\(\) cannot be negative"
with pytest.raises(ValueError, match=msg):
kfold(nrows=-1, nsplits=1)
msg = r"Argument nsplits in function datatable.kfold\(\) cannot be negative"
with pytest.raises(ValueError, match=msg):
kfold(nrows=3, nsplits=-3)
msg = "The number of splits cannot be less than two"
with pytest.raises(ValueError, match=msg):
kfold(nrows=5, nsplits=0)
msg = "The number of splits cannot exceed the number of rows"
with pytest.raises(ValueError, match=msg):
kfold(nrows=1, nsplits=2)
def test_kfold_k_any(seed):
random.seed(seed)
k = 2 + int(random.expovariate(0.01))
n = k + int(random.expovariate(0.0001))
splits = kfold(nrows=n, nsplits=k)
h1 = n // k
h2 = n * (k-1) // k
assert len(splits) == k
assert splits[0] == (range(h1, n), range(0, h1))
assert splits[-1] == (range(0, h2), range(h2, n))
for j, split in enumerate(splits[1:-1], 1):
hl = j * n // k
hu = (j + 1) * n // k
assert split[1] == range(hl, hu)
assert isinstance(split[0], dt.Frame)
assert split[0].nrows + len(split[1]) == n
assert split[0].ncols == 1
assert split[0].to_list()[0] == list(range(0, hl)) + list(range(hu, n))
def test_kfold_api():
assert_type_error(lambda: kfold(),
"Required parameter `nrows` is missing")
assert_type_error(lambda: kfold(nrows=5),
"Required parameter `nsplits` is missing")
assert_type_error(lambda: kfold(nrows=5, nsplits=2, seed=12345),
"kfold() got an unexpected keyword argument `seed`")
assert_type_error(lambda: kfold(5, 2),
"kfold() takes no positional arguments, but 2 were given")
assert_type_error(lambda: kfold(nrows=5, nsplits=3.3),
"Argument `nsplits` in kfold() should be an integer")
assert_type_error(lambda: kfold(nrows=None, nsplits=7),
"Argument `nrows` in kfold() should be an integer")
def test_kfold_simple():
splits = kfold(nrows=2, nsplits=2)
assert splits == [(range(1, 2), range(0, 1)),
(range(0, 1), range(1, 2))]
def test_kfold_api():
msg = "Required parameter nrows is missing"
with pytest.raises(TypeError, match=msg):
kfold()
msg = "Required parameter nsplits is missing"
with pytest.raises(TypeError, match=msg):
kfold(nrows=5)
msg = r"kfold\(\) got an unexpected keyword argument seed"
with pytest.raises(TypeError, match=msg):
kfold(nrows=5, nsplits=2, seed=12345)
msg = r"kfold\(\) takes no positional arguments, but 2 were given"
with pytest.raises(TypeError, match=msg):
kfold(5, 2)
msg = r"Argument nsplits in function datatable.kfold\(\) should be an integer"
with pytest.raises(TypeError, match=msg):
kfold(nrows=5, nsplits=3.3)
msg = r"Argument nrows in function datatable.kfold\(\) should be an integer"
with pytest.raises(TypeError, match=msg):
kfold(nrows=None, nsplits=7)
