Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

TST: Add test for pd.read_csv date parsing not working with dtype_backend="pyarrow" and missing values #60286

Merged
merged 7 commits into from
Nov 15, 2024
Merged

TST: Add test for pd.read_csv date parsing not working with dtype_backend="pyarrow" and missing values #60286

Changes from 3 commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
babed36
add test func
KevsterAmp Nov 12, 2024
574d129
remove io since StringIO is already imported
KevsterAmp Nov 12, 2024
5a9a935
add td.skip_if_no("pyarrow") from CI errors
KevsterAmp Nov 12, 2024
b2602cc
Merge remote-tracking branch 'upstream/main' into add-dataframe-pyarr…
KevsterAmp Nov 14, 2024
30b2149
fix test
KevsterAmp Nov 14, 2024
4812f69
improve expect_data; remove assert on "date" column dtype
KevsterAmp Nov 15, 2024
44164ce
Merge remote-tracking branch 'upstream/main' into add-dataframe-pyarr…
KevsterAmp Nov 15, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 9 additions & 0 deletions pandas/tests/io/test_common.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -674,3 +674,12 @@ def test_pickle_reader(reader):
# GH 22265
with BytesIO() as buffer:
pickle.dump(reader, buffer)


@td.skip_if_no("pyarrow")
def test_pyarrow_read_csv_datetime_dtype():
data = "date,id\n20/12/2025,a\n,b\n31/12/2020,c"
df = pd.read_csv(
StringIO(data), parse_dates=["date"], dayfirst=True, dtype_backend="pyarrow"
)
assert (df["date"].dtype) == "datetime64[s]"
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Can you build an expected DataFrame and use tm.assert_frame_equal?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Having a bit of struggle with the dtype casting, Tried two methods:

    # put dtype string[pyarrow] on the Series
    expected = pd.DataFrame(
        {
            "date": pd.Series(
                pd.to_datetime(["20/12/2025", pd.NaT, "31/12/2020"], dayfirst=True),
            ),
            "id": pd.Series(["a", "b", "c"], dtype="string[pyarrow]"),
        },
    )
    
    ###############
    
    # cast dtype using .astype()
    expected["id"] = expected["id"].astype("string[pyarrow]")

Returns error:

E       AssertionError: Attributes of DataFrame.iloc[:, 1] (column name="id") are different
E
E       Attribute "dtype" are different
E       [left]:  StringDtype(storage=pyarrow, na_value=<NA>)
E       [right]: string[pyarrow]

For a band-aid fix, I tried casting string[pyarrow] as well to the same column in the df variable.

@td.skip_if_no("pyarrow")
def test_pyarrow_read_csv_datetime_dtype():
    data = "date,id\n20/12/2025,a\n,b\n31/12/2020,c"
    df = pd.read_csv(
        StringIO(data), parse_dates=["date"], dayfirst=True, dtype_backend="pyarrow"
    )
    expected = pd.DataFrame(
        {
            "date": pd.Series(
                pd.to_datetime(["20/12/2025", pd.NaT, "31/12/2020"], dayfirst=True),
            ),
            "id": pd.Series(["a", "b", "c"], dtype="string[pyarrow]"),
        },
    )
    expected["id"] = expected["id"].astype("string[pyarrow]")
    df["id"] = df["id"].astype("string[pyarrow]")

    assert tm.assert_frame_equal(expected, df)
    assert (df["date"].dtype) == "datetime64[s]"

But for some reason, pytest returns:

>       assert tm.assert_frame_equal(expected, df)
E       AssertionError

Hard to check what's the error exaclty, since the error isn't verbose.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Based on the simplifying the bug report, I don't think we need the string column, only the "date" column.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@mroeschke - Tried this:

@td.skip_if_no("pyarrow")
def test_pyarrow_read_csv_datetime_dtype():
    # GH 59904
    data = '"date"\n"20/12/2025"\n""\n"31/12/2020"'
    result = pd.read_csv(
        StringIO(data), parse_dates=["date"], dayfirst=True, dtype_backend="pyarrow"
    )
    expected_dict = {
        "date": pd.Series(
            pd.to_datetime(["20/12/2025", pd.NaT, "31/12/2020"], dayfirst=True)
        )
    }
    expected = pd.DataFrame(expected_dict)

    assert (result["date"].dtype) == "datetime64[s]"
    assert tm.assert_frame_equal(expected, result)

Still returns assertion error

>       assert tm.assert_frame_equal(expected, result)
E       AssertionError

pandas/tests/io/test_common.py:696: AssertionError

Copy link
Contributor Author

@KevsterAmp KevsterAmp Nov 14, 2024 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Finally saw the problem lol
tm.assert_frame_equal should be run without assert. That's why it was showing AssertionError 😆

    assert tm.assert_frame_equal(expect, result) # returns AssertionError

    tm.assert_frame_equal(expect, result) # passes

Fixed it now and the test is passing