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import numpy as np
import pytest
from pandas._config import using_pyarrow_string_dtype
from pandas.errors import ChainedAssignmentError
import pandas.util._test_decorators as td
from pandas import (
DataFrame,
NaT,
Series,
date_range,
)
import pandas._testing as tm
class TestDataFrameInterpolate:
def test_interpolate_complex(self):
# GH#53635
ser = Series([complex("1+1j"), float("nan"), complex("2+2j")])
assert ser.dtype.kind == "c"
res = ser.interpolate()
expected = Series([ser[0], ser[0] * 1.5, ser[2]])
tm.assert_series_equal(res, expected)
df = ser.to_frame()
res = df.interpolate()
expected = expected.to_frame()
tm.assert_frame_equal(res, expected)
def test_interpolate_datetimelike_values(self, frame_or_series):
# GH#11312, GH#51005
orig = Series(date_range("2012-01-01", periods=5))
ser = orig.copy()
ser[2] = NaT
res = frame_or_series(ser).interpolate()
expected = frame_or_series(orig)
tm.assert_equal(res, expected)
# datetime64tz cast
ser_tz = ser.dt.tz_localize("US/Pacific")
res_tz = frame_or_series(ser_tz).interpolate()
expected_tz = frame_or_series(orig.dt.tz_localize("US/Pacific"))
tm.assert_equal(res_tz, expected_tz)
# timedelta64 cast
ser_td = ser - ser[0]
res_td = frame_or_series(ser_td).interpolate()
expected_td = frame_or_series(orig - orig[0])
tm.assert_equal(res_td, expected_td)
def test_interpolate_inplace(self, frame_or_series, using_array_manager, request):
# GH#44749
if using_array_manager and frame_or_series is DataFrame:
mark = pytest.mark.xfail(reason=".values-based in-place check is invalid")
request.applymarker(mark)
obj = frame_or_series([1, np.nan, 2])
orig = obj.values
obj.interpolate(inplace=True)
expected = frame_or_series([1, 1.5, 2])
tm.assert_equal(obj, expected)
# check we operated *actually* inplace
assert np.shares_memory(orig, obj.values)
assert orig.squeeze()[1] == 1.5
@pytest.mark.xfail(
using_pyarrow_string_dtype(), reason="interpolate doesn't work for string"
)
def test_interp_basic(self, using_copy_on_write):
df = DataFrame(
{
"A": [1, 2, np.nan, 4],
"B": [1, 4, 9, np.nan],
"C": [1, 2, 3, 5],
"D": list("abcd"),
}
)
expected = DataFrame(
{
"A": [1.0, 2.0, 3.0, 4.0],
"B": [1.0, 4.0, 9.0, 9.0],
"C": [1, 2, 3, 5],
"D": list("abcd"),
}
)
msg = "DataFrame.interpolate with object dtype"
with tm.assert_produces_warning(FutureWarning, match=msg):
result = df.interpolate()
tm.assert_frame_equal(result, expected)
# check we didn't operate inplace GH#45791
cvalues = df["C"]._values
dvalues = df["D"].values
if using_copy_on_write:
assert np.shares_memory(cvalues, result["C"]._values)
assert np.shares_memory(dvalues, result["D"]._values)
else:
assert not np.shares_memory(cvalues, result["C"]._values)
assert not np.shares_memory(dvalues, result["D"]._values)
with tm.assert_produces_warning(FutureWarning, match=msg):
res = df.interpolate(inplace=True)
assert res is None
tm.assert_frame_equal(df, expected)
# check we DID operate inplace
assert np.shares_memory(df["C"]._values, cvalues)
assert np.shares_memory(df["D"]._values, dvalues)
@pytest.mark.xfail(
using_pyarrow_string_dtype(), reason="interpolate doesn't work for string"
)
def test_interp_basic_with_non_range_index(self, using_infer_string):
df = DataFrame(
{
"A": [1, 2, np.nan, 4],
"B": [1, 4, 9, np.nan],
"C": [1, 2, 3, 5],
"D": list("abcd"),
}
)
msg = "DataFrame.interpolate with object dtype"
warning = FutureWarning if not using_infer_string else None
with tm.assert_produces_warning(warning, match=msg):
result = df.set_index("C").interpolate()
expected = df.set_index("C")
expected.loc[3, "A"] = 3
expected.loc[5, "B"] = 9
tm.assert_frame_equal(result, expected)
def test_interp_empty(self):
# https://github.com/pandas-dev/pandas/issues/35598
df = DataFrame()
result = df.interpolate()
assert result is not df
expected = df
tm.assert_frame_equal(result, expected)
def test_interp_bad_method(self):
df = DataFrame(
{
"A": [1, 2, np.nan, 4],
"B": [1, 4, 9, np.nan],
"C": [1, 2, 3, 5],
}
)
msg = (
r"method must be one of \['linear', 'time', 'index', 'values', "
r"'nearest', 'zero', 'slinear', 'quadratic', 'cubic', "
r"'barycentric', 'krogh', 'spline', 'polynomial', "
r"'from_derivatives', 'piecewise_polynomial', 'pchip', 'akima', "
r"'cubicspline'\]. Got 'not_a_method' instead."
)
with pytest.raises(ValueError, match=msg):
df.interpolate(method="not_a_method")
def test_interp_combo(self):
df = DataFrame(
{
"A": [1.0, 2.0, np.nan, 4.0],
"B": [1, 4, 9, np.nan],
"C": [1, 2, 3, 5],
"D": list("abcd"),
}
)
result = df["A"].interpolate()
expected = Series([1.0, 2.0, 3.0, 4.0], name="A")
tm.assert_series_equal(result, expected)
msg = "The 'downcast' keyword in Series.interpolate is deprecated"
with tm.assert_produces_warning(FutureWarning, match=msg):
result = df["A"].interpolate(downcast="infer")
expected = Series([1, 2, 3, 4], name="A")
tm.assert_series_equal(result, expected)
def test_inerpolate_invalid_downcast(self):
# GH#53103
df = DataFrame(
{
"A": [1.0, 2.0, np.nan, 4.0],
"B": [1, 4, 9, np.nan],
"C": [1, 2, 3, 5],
"D": list("abcd"),
}
)
msg = "downcast must be either None or 'infer'"
msg2 = "The 'downcast' keyword in DataFrame.interpolate is deprecated"
msg3 = "The 'downcast' keyword in Series.interpolate is deprecated"
with pytest.raises(ValueError, match=msg):
with tm.assert_produces_warning(FutureWarning, match=msg2):
df.interpolate(downcast="int64")
with pytest.raises(ValueError, match=msg):
with tm.assert_produces_warning(FutureWarning, match=msg3):
df["A"].interpolate(downcast="int64")
def test_interp_nan_idx(self):
df = DataFrame({"A": [1, 2, np.nan, 4], "B": [np.nan, 2, 3, 4]})
df = df.set_index("A")
msg = (
"Interpolation with NaNs in the index has not been implemented. "
"Try filling those NaNs before interpolating."
)
with pytest.raises(NotImplementedError, match=msg):
df.interpolate(method="values")
def test_interp_various(self):
pytest.importorskip("scipy")
df = DataFrame(
{"A": [1, 2, np.nan, 4, 5, np.nan, 7], "C": [1, 2, 3, 5, 8, 13, 21]}
)
df = df.set_index("C")
expected = df.copy()
result = df.interpolate(method="polynomial", order=1)
expected.loc[3, "A"] = 2.66666667
expected.loc[13, "A"] = 5.76923076
tm.assert_frame_equal(result, expected)
result = df.interpolate(method="cubic")
# GH #15662.
expected.loc[3, "A"] = 2.81547781
expected.loc[13, "A"] = 5.52964175
tm.assert_frame_equal(result, expected)
result = df.interpolate(method="nearest")
expected.loc[3, "A"] = 2
expected.loc[13, "A"] = 5
tm.assert_frame_equal(result, expected, check_dtype=False)
result = df.interpolate(method="quadratic")
expected.loc[3, "A"] = 2.82150771
expected.loc[13, "A"] = 6.12648668
tm.assert_frame_equal(result, expected)
result = df.interpolate(method="slinear")
expected.loc[3, "A"] = 2.66666667
expected.loc[13, "A"] = 5.76923077
tm.assert_frame_equal(result, expected)
result = df.interpolate(method="zero")
expected.loc[3, "A"] = 2.0
expected.loc[13, "A"] = 5
tm.assert_frame_equal(result, expected, check_dtype=False)
def test_interp_alt_scipy(self):
pytest.importorskip("scipy")
df = DataFrame(
{"A": [1, 2, np.nan, 4, 5, np.nan, 7], "C": [1, 2, 3, 5, 8, 13, 21]}
)
result = df.interpolate(method="barycentric")
expected = df.copy()
expected.loc[2, "A"] = 3
expected.loc[5, "A"] = 6
tm.assert_frame_equal(result, expected)
msg = "The 'downcast' keyword in DataFrame.interpolate is deprecated"
with tm.assert_produces_warning(FutureWarning, match=msg):
result = df.interpolate(method="barycentric", downcast="infer")
tm.assert_frame_equal(result, expected.astype(np.int64))
result = df.interpolate(method="krogh")
expectedk = df.copy()
expectedk["A"] = expected["A"]
tm.assert_frame_equal(result, expectedk)
result = df.interpolate(method="pchip")
expected.loc[2, "A"] = 3
expected.loc[5, "A"] = 6.0
tm.assert_frame_equal(result, expected)
def test_interp_rowwise(self):
df = DataFrame(
{
0: [1, 2, np.nan, 4],
1: [2, 3, 4, np.nan],
2: [np.nan, 4, 5, 6],
3: [4, np.nan, 6, 7],
4: [1, 2, 3, 4],
}
)
result = df.interpolate(axis=1)
expected = df.copy()
expected.loc[3, 1] = 5
expected.loc[0, 2] = 3
expected.loc[1, 3] = 3
expected[4] = expected[4].astype(np.float64)
tm.assert_frame_equal(result, expected)
result = df.interpolate(axis=1, method="values")
tm.assert_frame_equal(result, expected)
result = df.interpolate(axis=0)
expected = df.interpolate()
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize(
"axis_name, axis_number",
[
pytest.param("rows", 0, id="rows_0"),
pytest.param("index", 0, id="index_0"),
pytest.param("columns", 1, id="columns_1"),
],
)
def test_interp_axis_names(self, axis_name, axis_number):
# GH 29132: test axis names
data = {0: [0, np.nan, 6], 1: [1, np.nan, 7], 2: [2, 5, 8]}
df = DataFrame(data, dtype=np.float64)
result = df.interpolate(axis=axis_name, method="linear")
expected = df.interpolate(axis=axis_number, method="linear")
tm.assert_frame_equal(result, expected)
def test_rowwise_alt(self):
df = DataFrame(
{
0: [0, 0.5, 1.0, np.nan, 4, 8, np.nan, np.nan, 64],
1: [1, 2, 3, 4, 3, 2, 1, 0, -1],
}
)
df.interpolate(axis=0)
# TODO: assert something?
@pytest.mark.parametrize(
"check_scipy", [False, pytest.param(True, marks=td.skip_if_no("scipy"))]
)
def test_interp_leading_nans(self, check_scipy):
df = DataFrame(
{"A": [np.nan, np.nan, 0.5, 0.25, 0], "B": [np.nan, -3, -3.5, np.nan, -4]}
)
result = df.interpolate()
expected = df.copy()
expected.loc[3, "B"] = -3.75
tm.assert_frame_equal(result, expected)
if check_scipy:
result = df.interpolate(method="polynomial", order=1)
tm.assert_frame_equal(result, expected)
def test_interp_raise_on_only_mixed(self, axis):
df = DataFrame(
{
"A": [1, 2, np.nan, 4],
"B": ["a", "b", "c", "d"],
"C": [np.nan, 2, 5, 7],
"D": [np.nan, np.nan, 9, 9],
"E": [1, 2, 3, 4],
}
)
msg = (
"Cannot interpolate with all object-dtype columns "
"in the DataFrame. Try setting at least one "
"column to a numeric dtype."
)
with pytest.raises(TypeError, match=msg):
df.astype("object").interpolate(axis=axis)
def test_interp_raise_on_all_object_dtype(self):
# GH 22985
df = DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]}, dtype="object")
msg = (
"Cannot interpolate with all object-dtype columns "
"in the DataFrame. Try setting at least one "
"column to a numeric dtype."
)
with pytest.raises(TypeError, match=msg):
df.interpolate()
def test_interp_inplace(self, using_copy_on_write):
df = DataFrame({"a": [1.0, 2.0, np.nan, 4.0]})
expected = DataFrame({"a": [1.0, 2.0, 3.0, 4.0]})
expected_cow = df.copy()
result = df.copy()
if using_copy_on_write:
with tm.raises_chained_assignment_error():
return_value = result["a"].interpolate(inplace=True)
assert return_value is None
tm.assert_frame_equal(result, expected_cow)
else:
with tm.assert_produces_warning(FutureWarning, match="inplace method"):
return_value = result["a"].interpolate(inplace=True)
assert return_value is None
tm.assert_frame_equal(result, expected)
result = df.copy()
msg = "The 'downcast' keyword in Series.interpolate is deprecated"
if using_copy_on_write:
with tm.assert_produces_warning(
(FutureWarning, ChainedAssignmentError), match=msg
):
return_value = result["a"].interpolate(inplace=True, downcast="infer")
assert return_value is None
tm.assert_frame_equal(result, expected_cow)
else:
with tm.assert_produces_warning(FutureWarning, match=msg):
return_value = result["a"].interpolate(inplace=True, downcast="infer")
assert return_value is None
tm.assert_frame_equal(result, expected.astype("int64"))
def test_interp_inplace_row(self):
# GH 10395
result = DataFrame(
{"a": [1.0, 2.0, 3.0, 4.0], "b": [np.nan, 2.0, 3.0, 4.0], "c": [3, 2, 2, 2]}
)
expected = result.interpolate(method="linear", axis=1, inplace=False)
return_value = result.interpolate(method="linear", axis=1, inplace=True)
assert return_value is None
tm.assert_frame_equal(result, expected)
def test_interp_ignore_all_good(self):
# GH
df = DataFrame(
{
"A": [1, 2, np.nan, 4],
"B": [1, 2, 3, 4],
"C": [1.0, 2.0, np.nan, 4.0],
"D": [1.0, 2.0, 3.0, 4.0],
}
)
expected = DataFrame(
{
"A": np.array([1, 2, 3, 4], dtype="float64"),
"B": np.array([1, 2, 3, 4], dtype="int64"),
"C": np.array([1.0, 2.0, 3, 4.0], dtype="float64"),
"D": np.array([1.0, 2.0, 3.0, 4.0], dtype="float64"),
}
)
msg = "The 'downcast' keyword in DataFrame.interpolate is deprecated"
with tm.assert_produces_warning(FutureWarning, match=msg):
result = df.interpolate(downcast=None)
tm.assert_frame_equal(result, expected)
# all good
with tm.assert_produces_warning(FutureWarning, match=msg):
result = df[["B", "D"]].interpolate(downcast=None)
tm.assert_frame_equal(result, df[["B", "D"]])
def test_interp_time_inplace_axis(self):
# GH 9687
periods = 5
idx = date_range(start="2014-01-01", periods=periods)
data = np.random.default_rng(2).random((periods, periods))
data[data < 0.5] = np.nan
expected = DataFrame(index=idx, columns=idx, data=data)
result = expected.interpolate(axis=0, method="time")
return_value = expected.interpolate(axis=0, method="time", inplace=True)
assert return_value is None
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize("axis_name, axis_number", [("index", 0), ("columns", 1)])
def test_interp_string_axis(self, axis_name, axis_number):
# https://github.com/pandas-dev/pandas/issues/25190
x = np.linspace(0, 100, 1000)
y = np.sin(x)
df = DataFrame(
data=np.tile(y, (10, 1)), index=np.arange(10), columns=x
).reindex(columns=x * 1.005)
result = df.interpolate(method="linear", axis=axis_name)
expected = df.interpolate(method="linear", axis=axis_number)
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize("multiblock", [True, False])
@pytest.mark.parametrize("method", ["ffill", "bfill", "pad"])
def test_interp_fillna_methods(
self, request, axis, multiblock, method, using_array_manager
):
# GH 12918
if using_array_manager and axis in (1, "columns"):
# TODO(ArrayManager) support axis=1
td.mark_array_manager_not_yet_implemented(request)
df = DataFrame(
{
"A": [1.0, 2.0, 3.0, 4.0, np.nan, 5.0],
"B": [2.0, 4.0, 6.0, np.nan, 8.0, 10.0],
"C": [3.0, 6.0, 9.0, np.nan, np.nan, 30.0],
}
)
if multiblock:
df["D"] = np.nan
df["E"] = 1.0
method2 = method if method != "pad" else "ffill"
expected = getattr(df, method2)(axis=axis)
msg = f"DataFrame.interpolate with method={method} is deprecated"
with tm.assert_produces_warning(FutureWarning, match=msg):
result = df.interpolate(method=method, axis=axis)
tm.assert_frame_equal(result, expected)
def test_interpolate_empty_df(self):
# GH#53199
df = DataFrame()
expected = df.copy()
result = df.interpolate(inplace=True)
assert result is None
tm.assert_frame_equal(df, expected)
def test_interpolate_ea(self, any_int_ea_dtype):
# GH#55347
df = DataFrame({"a": [1, None, None, None, 3]}, dtype=any_int_ea_dtype)
orig = df.copy()
result = df.interpolate(limit=2)
expected = DataFrame({"a": [1, 1.5, 2.0, None, 3]}, dtype="Float64")
tm.assert_frame_equal(result, expected)
tm.assert_frame_equal(df, orig)
@pytest.mark.parametrize(
"dtype",
[
"Float64",
"Float32",
pytest.param("float32[pyarrow]", marks=td.skip_if_no("pyarrow")),
pytest.param("float64[pyarrow]", marks=td.skip_if_no("pyarrow")),
],
)
def test_interpolate_ea_float(self, dtype):
# GH#55347
df = DataFrame({"a": [1, None, None, None, 3]}, dtype=dtype)
orig = df.copy()
result = df.interpolate(limit=2)
expected = DataFrame({"a": [1, 1.5, 2.0, None, 3]}, dtype=dtype)
tm.assert_frame_equal(result, expected)
tm.assert_frame_equal(df, orig)
@pytest.mark.parametrize(
"dtype",
["int64", "uint64", "int32", "int16", "int8", "uint32", "uint16", "uint8"],
)
def test_interpolate_arrow(self, dtype):
# GH#55347
pytest.importorskip("pyarrow")
df = DataFrame({"a": [1, None, None, None, 3]}, dtype=dtype + "[pyarrow]")
result = df.interpolate(limit=2)
expected = DataFrame({"a": [1, 1.5, 2.0, None, 3]}, dtype="float64[pyarrow]")
tm.assert_frame_equal(result, expected)