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.venv/Lib/site-packages/pandas/tests/frame/indexing/test_mask.py

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+"""
+Tests for DataFrame.mask; tests DataFrame.where as a side-effect.
+"""
+
+import numpy as np
+
+from pandas import (
+    NA,
+    DataFrame,
+    Series,
+    StringDtype,
+    Timedelta,
+    isna,
+)
+import pandas._testing as tm
+
+
+class TestDataFrameMask:
+    def test_mask(self):
+        df = DataFrame(np.random.randn(5, 3))
+        cond = df > 0
+
+        rs = df.where(cond, np.nan)
+        tm.assert_frame_equal(rs, df.mask(df <= 0))
+        tm.assert_frame_equal(rs, df.mask(~cond))
+
+        other = DataFrame(np.random.randn(5, 3))
+        rs = df.where(cond, other)
+        tm.assert_frame_equal(rs, df.mask(df <= 0, other))
+        tm.assert_frame_equal(rs, df.mask(~cond, other))
+
+    def test_mask2(self):
+        # see GH#21891
+        df = DataFrame([1, 2])
+        res = df.mask([[True], [False]])
+
+        exp = DataFrame([np.nan, 2])
+        tm.assert_frame_equal(res, exp)
+
+    def test_mask_inplace(self):
+        # GH#8801
+        df = DataFrame(np.random.randn(5, 3))
+        cond = df > 0
+
+        rdf = df.copy()
+
+        return_value = rdf.where(cond, inplace=True)
+        assert return_value is None
+        tm.assert_frame_equal(rdf, df.where(cond))
+        tm.assert_frame_equal(rdf, df.mask(~cond))
+
+        rdf = df.copy()
+        return_value = rdf.where(cond, -df, inplace=True)
+        assert return_value is None
+        tm.assert_frame_equal(rdf, df.where(cond, -df))
+        tm.assert_frame_equal(rdf, df.mask(~cond, -df))
+
+    def test_mask_edge_case_1xN_frame(self):
+        # GH#4071
+        df = DataFrame([[1, 2]])
+        res = df.mask(DataFrame([[True, False]]))
+        expec = DataFrame([[np.nan, 2]])
+        tm.assert_frame_equal(res, expec)
+
+    def test_mask_callable(self):
+        # GH#12533
+        df = DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
+        result = df.mask(lambda x: x > 4, lambda x: x + 1)
+        exp = DataFrame([[1, 2, 3], [4, 6, 7], [8, 9, 10]])
+        tm.assert_frame_equal(result, exp)
+        tm.assert_frame_equal(result, df.mask(df > 4, df + 1))
+
+        # return ndarray and scalar
+        result = df.mask(lambda x: (x % 2 == 0).values, lambda x: 99)
+        exp = DataFrame([[1, 99, 3], [99, 5, 99], [7, 99, 9]])
+        tm.assert_frame_equal(result, exp)
+        tm.assert_frame_equal(result, df.mask(df % 2 == 0, 99))
+
+        # chain
+        result = (df + 2).mask(lambda x: x > 8, lambda x: x + 10)
+        exp = DataFrame([[3, 4, 5], [6, 7, 8], [19, 20, 21]])
+        tm.assert_frame_equal(result, exp)
+        tm.assert_frame_equal(result, (df + 2).mask((df + 2) > 8, (df + 2) + 10))
+
+    def test_mask_dtype_bool_conversion(self):
+        # GH#3733
+        df = DataFrame(data=np.random.randn(100, 50))
+        df = df.where(df > 0)  # create nans
+        bools = df > 0
+        mask = isna(df)
+        expected = bools.astype(object).mask(mask)
+        result = bools.mask(mask)
+        tm.assert_frame_equal(result, expected)
+
+    def test_mask_pos_args_deprecation(self, frame_or_series):
+        # https://github.com/pandas-dev/pandas/issues/41485
+        obj = DataFrame({"a": range(5)})
+        expected = DataFrame({"a": [-1, 1, -1, 3, -1]})
+        obj = tm.get_obj(obj, frame_or_series)
+        expected = tm.get_obj(expected, frame_or_series)
+
+        cond = obj % 2 == 0
+        msg = (
+            r"In a future version of pandas all arguments of "
+            f"{frame_or_series.__name__}.mask except for "
+            r"the arguments 'cond' and 'other' will be keyword-only"
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = obj.mask(cond, -1, False)
+        tm.assert_equal(result, expected)
+
+
+def test_mask_try_cast_deprecated(frame_or_series):
+
+    obj = DataFrame(np.random.randn(4, 3))
+    if frame_or_series is not DataFrame:
+        obj = obj[0]
+
+    mask = obj > 0
+
+    with tm.assert_produces_warning(FutureWarning):
+        # try_cast keyword deprecated
+        obj.mask(mask, -1, try_cast=True)
+
+
+def test_mask_stringdtype(frame_or_series):
+    # GH 40824
+    obj = DataFrame(
+        {"A": ["foo", "bar", "baz", NA]},
+        index=["id1", "id2", "id3", "id4"],
+        dtype=StringDtype(),
+    )
+    filtered_obj = DataFrame(
+        {"A": ["this", "that"]}, index=["id2", "id3"], dtype=StringDtype()
+    )
+    expected = DataFrame(
+        {"A": [NA, "this", "that", NA]},
+        index=["id1", "id2", "id3", "id4"],
+        dtype=StringDtype(),
+    )
+    if frame_or_series is Series:
+        obj = obj["A"]
+        filtered_obj = filtered_obj["A"]
+        expected = expected["A"]
+
+    filter_ser = Series([False, True, True, False])
+    result = obj.mask(filter_ser, filtered_obj)
+
+    tm.assert_equal(result, expected)
+
+
+def test_mask_where_dtype_timedelta():
+    # https://github.com/pandas-dev/pandas/issues/39548
+    df = DataFrame([Timedelta(i, unit="d") for i in range(5)])
+
+    expected = DataFrame(np.full(5, np.nan, dtype="timedelta64[ns]"))
+    tm.assert_frame_equal(df.mask(df.notna()), expected)
+
+    expected = DataFrame(
+        [np.nan, np.nan, np.nan, Timedelta("3 day"), Timedelta("4 day")]
+    )
+    tm.assert_frame_equal(df.where(df > Timedelta(2, unit="d")), expected)