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import numpy as np
import pytest
from pandas import (
DataFrame,
MultiIndex,
Series,
concat,
date_range,
)
import pandas._testing as tm
from pandas.api.indexers import (
BaseIndexer,
FixedForwardWindowIndexer,
)
from pandas.core.indexers.objects import (
ExpandingIndexer,
FixedWindowIndexer,
VariableOffsetWindowIndexer,
)
from pandas.tseries.offsets import BusinessDay
def test_bad_get_window_bounds_signature():
class BadIndexer(BaseIndexer):
def get_window_bounds(self):
return None
indexer = BadIndexer()
with pytest.raises(ValueError, match="BadIndexer does not implement"):
Series(range(5)).rolling(indexer)
def test_expanding_indexer():
s = Series(range(10))
indexer = ExpandingIndexer()
result = s.rolling(indexer).mean()
expected = s.expanding().mean()
tm.assert_series_equal(result, expected)
def test_indexer_constructor_arg():
# Example found in computation.rst
use_expanding = [True, False, True, False, True]
df = DataFrame({"values": range(5)})
class CustomIndexer(BaseIndexer):
def get_window_bounds(self, num_values, min_periods, center, closed, step):
start = np.empty(num_values, dtype=np.int64)
end = np.empty(num_values, dtype=np.int64)
for i in range(num_values):
if self.use_expanding[i]:
start[i] = 0
end[i] = i + 1
else:
start[i] = i
end[i] = i + self.window_size
return start, end
indexer = CustomIndexer(window_size=1, use_expanding=use_expanding)
result = df.rolling(indexer).sum()
expected = DataFrame({"values": [0.0, 1.0, 3.0, 3.0, 10.0]})
tm.assert_frame_equal(result, expected)
def test_indexer_accepts_rolling_args():
df = DataFrame({"values": range(5)})
class CustomIndexer(BaseIndexer):
def get_window_bounds(self, num_values, min_periods, center, closed, step):
start = np.empty(num_values, dtype=np.int64)
end = np.empty(num_values, dtype=np.int64)
for i in range(num_values):
if (
center
and min_periods == 1
and closed == "both"
and step == 1
and i == 2
):
start[i] = 0
end[i] = num_values
else:
start[i] = i
end[i] = i + self.window_size
return start, end
indexer = CustomIndexer(window_size=1)
result = df.rolling(
indexer, center=True, min_periods=1, closed="both", step=1
).sum()
expected = DataFrame({"values": [0.0, 1.0, 10.0, 3.0, 4.0]})
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize(
"func,np_func,expected,np_kwargs",
[
("count", len, [3.0, 3.0, 3.0, 3.0, 3.0, 3.0, 3.0, 3.0, 2.0, np.nan], {}),
("min", np.min, [0.0, 1.0, 2.0, 3.0, 4.0, 6.0, 6.0, 7.0, 8.0, np.nan], {}),
(
"max",
np.max,
[2.0, 3.0, 4.0, 100.0, 100.0, 100.0, 8.0, 9.0, 9.0, np.nan],
{},
),
(
"std",
np.std,
[
1.0,
1.0,
1.0,
55.71654452,
54.85739087,
53.9845657,
1.0,
1.0,
0.70710678,
np.nan,
],
{"ddof": 1},
),
(
"var",
np.var,
[
1.0,
1.0,
1.0,
3104.333333,
3009.333333,
2914.333333,
1.0,
1.0,
0.500000,
np.nan,
],
{"ddof": 1},
),
(
"median",
np.median,
[1.0, 2.0, 3.0, 4.0, 6.0, 7.0, 7.0, 8.0, 8.5, np.nan],
{},
),
],
)
def test_rolling_forward_window(
frame_or_series, func, np_func, expected, np_kwargs, step
):
# GH 32865
values = np.arange(10.0)
values[5] = 100.0
indexer = FixedForwardWindowIndexer(window_size=3)
match = "Forward-looking windows can't have center=True"
with pytest.raises(ValueError, match=match):
rolling = frame_or_series(values).rolling(window=indexer, center=True)
getattr(rolling, func)()
match = "Forward-looking windows don't support setting the closed argument"
with pytest.raises(ValueError, match=match):
rolling = frame_or_series(values).rolling(window=indexer, closed="right")
getattr(rolling, func)()
rolling = frame_or_series(values).rolling(window=indexer, min_periods=2, step=step)
result = getattr(rolling, func)()
# Check that the function output matches the explicitly provided array
expected = frame_or_series(expected)[::step]
tm.assert_equal(result, expected)
# Check that the rolling function output matches applying an alternative
# function to the rolling window object
expected2 = frame_or_series(rolling.apply(lambda x: np_func(x, **np_kwargs)))
tm.assert_equal(result, expected2)
# Check that the function output matches applying an alternative function
# if min_periods isn't specified
# GH 39604: After count-min_periods deprecation, apply(lambda x: len(x))
# is equivalent to count after setting min_periods=0
min_periods = 0 if func == "count" else None
rolling3 = frame_or_series(values).rolling(window=indexer, min_periods=min_periods)
result3 = getattr(rolling3, func)()
expected3 = frame_or_series(rolling3.apply(lambda x: np_func(x, **np_kwargs)))
tm.assert_equal(result3, expected3)
def test_rolling_forward_skewness(frame_or_series, step):
values = np.arange(10.0)
values[5] = 100.0
indexer = FixedForwardWindowIndexer(window_size=5)
rolling = frame_or_series(values).rolling(window=indexer, min_periods=3, step=step)
result = rolling.skew()
expected = frame_or_series(
[
0.0,
2.232396,
2.229508,
2.228340,
2.229091,
2.231989,
0.0,
0.0,
np.nan,
np.nan,
]
)[::step]
tm.assert_equal(result, expected)
@pytest.mark.parametrize(
"func,expected",
[
("cov", [2.0, 2.0, 2.0, 97.0, 2.0, -93.0, 2.0, 2.0, np.nan, np.nan]),
(
"corr",
[
1.0,
1.0,
1.0,
0.8704775290207161,
0.018229084250926637,
-0.861357304646493,
1.0,
1.0,
np.nan,
np.nan,
],
),
],
)
def test_rolling_forward_cov_corr(func, expected):
values1 = np.arange(10).reshape(-1, 1)
values2 = values1 * 2
values1[5, 0] = 100
values = np.concatenate([values1, values2], axis=1)
indexer = FixedForwardWindowIndexer(window_size=3)
rolling = DataFrame(values).rolling(window=indexer, min_periods=3)
# We are interested in checking only pairwise covariance / correlation
result = getattr(rolling, func)().loc[(slice(None), 1), 0]
result = result.reset_index(drop=True)
expected = Series(expected).reset_index(drop=True)
expected.name = result.name
tm.assert_equal(result, expected)
@pytest.mark.parametrize(
"closed,expected_data",
[
["right", [0.0, 1.0, 2.0, 3.0, 7.0, 12.0, 6.0, 7.0, 8.0, 9.0]],
["left", [0.0, 0.0, 1.0, 2.0, 5.0, 9.0, 5.0, 6.0, 7.0, 8.0]],
],
)
def test_non_fixed_variable_window_indexer(closed, expected_data):
index = date_range("2020", periods=10)
df = DataFrame(range(10), index=index)
offset = BusinessDay(1)
indexer = VariableOffsetWindowIndexer(index=index, offset=offset)
result = df.rolling(indexer, closed=closed).sum()
expected = DataFrame(expected_data, index=index)
tm.assert_frame_equal(result, expected)
def test_variableoffsetwindowindexer_not_dti():
# GH 54379
with pytest.raises(ValueError, match="index must be a DatetimeIndex."):
VariableOffsetWindowIndexer(index="foo", offset=BusinessDay(1))
def test_variableoffsetwindowindexer_not_offset():
# GH 54379
idx = date_range("2020", periods=10)
with pytest.raises(ValueError, match="offset must be a DateOffset-like object."):
VariableOffsetWindowIndexer(index=idx, offset="foo")
def test_fixed_forward_indexer_count(step):
# GH: 35579
df = DataFrame({"b": [None, None, None, 7]})
indexer = FixedForwardWindowIndexer(window_size=2)
result = df.rolling(window=indexer, min_periods=0, step=step).count()
expected = DataFrame({"b": [0.0, 0.0, 1.0, 1.0]})[::step]
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize(
("end_value", "values"), [(1, [0.0, 1, 1, 3, 2]), (-1, [0.0, 1, 0, 3, 1])]
)
@pytest.mark.parametrize(("func", "args"), [("median", []), ("quantile", [0.5])])
def test_indexer_quantile_sum(end_value, values, func, args):
# GH 37153
class CustomIndexer(BaseIndexer):
def get_window_bounds(self, num_values, min_periods, center, closed, step):
start = np.empty(num_values, dtype=np.int64)
end = np.empty(num_values, dtype=np.int64)
for i in range(num_values):
if self.use_expanding[i]:
start[i] = 0
end[i] = max(i + end_value, 1)
else:
start[i] = i
end[i] = i + self.window_size
return start, end
use_expanding = [True, False, True, False, True]
df = DataFrame({"values": range(5)})
indexer = CustomIndexer(window_size=1, use_expanding=use_expanding)
result = getattr(df.rolling(indexer), func)(*args)
expected = DataFrame({"values": values})
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize(
"indexer_class", [FixedWindowIndexer, FixedForwardWindowIndexer, ExpandingIndexer]
)
@pytest.mark.parametrize("window_size", [1, 2, 12])
@pytest.mark.parametrize(
"df_data",
[
{"a": [1, 1], "b": [0, 1]},
{"a": [1, 2], "b": [0, 1]},
{"a": [1] * 16, "b": [np.nan, 1, 2, np.nan] + list(range(4, 16))},
],
)
def test_indexers_are_reusable_after_groupby_rolling(
indexer_class, window_size, df_data
):
# GH 43267
df = DataFrame(df_data)
num_trials = 3
indexer = indexer_class(window_size=window_size)
original_window_size = indexer.window_size
for i in range(num_trials):
df.groupby("a")["b"].rolling(window=indexer, min_periods=1).mean()
assert indexer.window_size == original_window_size
@pytest.mark.parametrize(
"window_size, num_values, expected_start, expected_end",
[
(1, 1, [0], [1]),
(1, 2, [0, 1], [1, 2]),
(2, 1, [0], [1]),
(2, 2, [0, 1], [2, 2]),
(5, 12, range(12), list(range(5, 12)) + [12] * 5),
(12, 5, range(5), [5] * 5),
(0, 0, np.array([]), np.array([])),
(1, 0, np.array([]), np.array([])),
(0, 1, [0], [0]),
],
)
def test_fixed_forward_indexer_bounds(
window_size, num_values, expected_start, expected_end, step
):
# GH 43267
indexer = FixedForwardWindowIndexer(window_size=window_size)
start, end = indexer.get_window_bounds(num_values=num_values, step=step)
tm.assert_numpy_array_equal(
start, np.array(expected_start[::step]), check_dtype=False
)
tm.assert_numpy_array_equal(end, np.array(expected_end[::step]), check_dtype=False)
assert len(start) == len(end)
@pytest.mark.parametrize(
"df, window_size, expected",
[
(
DataFrame({"b": [0, 1, 2], "a": [1, 2, 2]}),
2,
Series(
[0, 1.5, 2.0],
index=MultiIndex.from_arrays([[1, 2, 2], range(3)], names=["a", None]),
name="b",
dtype=np.float64,
),
),
(
DataFrame(
{
"b": [np.nan, 1, 2, np.nan] + list(range(4, 18)),
"a": [1] * 7 + [2] * 11,
"c": range(18),
}
),
12,
Series(
[
3.6,
3.6,
4.25,
5.0,
5.0,
5.5,
6.0,
12.0,
12.5,
13.0,
13.5,
14.0,
14.5,
15.0,
15.5,
16.0,
16.5,
17.0,
],
index=MultiIndex.from_arrays(
[[1] * 7 + [2] * 11, range(18)], names=["a", None]
),
name="b",
dtype=np.float64,
),
),
],
)
def test_rolling_groupby_with_fixed_forward_specific(df, window_size, expected):
# GH 43267
indexer = FixedForwardWindowIndexer(window_size=window_size)
result = df.groupby("a")["b"].rolling(window=indexer, min_periods=1).mean()
tm.assert_series_equal(result, expected)
@pytest.mark.parametrize(
"group_keys",
[
(1,),
(1, 2),
(2, 1),
(1, 1, 2),
(1, 2, 1),
(1, 1, 2, 2),
(1, 2, 3, 2, 3),
(1, 1, 2) * 4,
(1, 2, 3) * 5,
],
)
@pytest.mark.parametrize("window_size", [1, 2, 3, 4, 5, 8, 20])
def test_rolling_groupby_with_fixed_forward_many(group_keys, window_size):
# GH 43267
df = DataFrame(
{
"a": np.array(list(group_keys)),
"b": np.arange(len(group_keys), dtype=np.float64) + 17,
"c": np.arange(len(group_keys), dtype=np.int64),
}
)
indexer = FixedForwardWindowIndexer(window_size=window_size)
result = df.groupby("a")["b"].rolling(window=indexer, min_periods=1).sum()
result.index.names = ["a", "c"]
groups = df.groupby("a")[["a", "b", "c"]]
manual = concat(
[
g.assign(
b=[
g["b"].iloc[i : i + window_size].sum(min_count=1)
for i in range(len(g))
]
)
for _, g in groups
]
)
manual = manual.set_index(["a", "c"])["b"]
tm.assert_series_equal(result, manual)
def test_unequal_start_end_bounds():
class CustomIndexer(BaseIndexer):
def get_window_bounds(self, num_values, min_periods, center, closed, step):
return np.array([1]), np.array([1, 2])
indexer = CustomIndexer()
roll = Series(1).rolling(indexer)
match = "start"
with pytest.raises(ValueError, match=match):
roll.mean()
with pytest.raises(ValueError, match=match):
next(iter(roll))
with pytest.raises(ValueError, match=match):
roll.corr(pairwise=True)
with pytest.raises(ValueError, match=match):
roll.cov(pairwise=True)
def test_unequal_bounds_to_object():
# GH 44470
class CustomIndexer(BaseIndexer):
def get_window_bounds(self, num_values, min_periods, center, closed, step):
return np.array([1]), np.array([2])
indexer = CustomIndexer()
roll = Series([1, 1]).rolling(indexer)
match = "start and end"
with pytest.raises(ValueError, match=match):
roll.mean()
with pytest.raises(ValueError, match=match):
next(iter(roll))
with pytest.raises(ValueError, match=match):
roll.corr(pairwise=True)
with pytest.raises(ValueError, match=match):
roll.cov(pairwise=True)