Method test_to_dask_dataframe

xarray/tests/test_dataarray.py:3768–3800

(self)

    @requires_dask
    @pytest.mark.xfail(not has_dask_ge_2025_1_0, reason="dask-expr is broken")
    def test_to_dask_dataframe(self) -> None:
        arr_np = np.arange(3 * 4).reshape(3, 4)
        arr = DataArray(arr_np, [("B", [1, 2, 3]), ("A", list("cdef"))], name="foo")
        expected_s = arr.to_series()
        actual = arr.to_dask_dataframe()["foo"]

        assert_array_equal(actual.values, np.asarray(expected_s.values))

        actual = arr.to_dask_dataframe(dim_order=["A", "B"])["foo"]
        assert_array_equal(arr_np.transpose().reshape(-1), actual.values)

        # regression test for coords with different dimensions

        arr.coords["C"] = ("B", [-1, -2, -3])
        expected_df = arr.to_series().to_frame()
        expected_df["C"] = [-1] * 4 + [-2] * 4 + [-3] * 4
        expected_df = expected_df[["C", "foo"]]
        actual = arr.to_dask_dataframe()[["C", "foo"]]

        assert_array_equal(expected_df.values, np.asarray(actual.values))
        assert_array_equal(
            expected_df.columns.values, np.asarray(actual.columns.values)
        )

        with pytest.raises(ValueError, match="does not match the set of dimensions"):
            arr.to_dask_dataframe(dim_order=["B", "A", "C"])

        arr.name = None
        with pytest.raises(
            ValueError,
            match="Cannot convert an unnamed DataArray",
        ):
            arr.to_dask_dataframe()

    def test_to_pandas_name_matches_coordinate(self) -> None:
        # coordinate with same name as array