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Merged
merged 4 commits into from
Aug 24, 2023
Merged

Incorrect reading of CSV containing large integers Issue#52505 #54679

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a7d8838
mend
kvn4 Aug 21, 2023
4429c6a
mmend
kvn4 Aug 23, 2023
6f23751
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kvn4 Aug 23, 2023
e2d51c4
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kvn4 Aug 24, 2023
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2 changes: 1 addition & 1 deletion doc/source/whatsnew/v2.2.0.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -139,7 +139,7 @@ Timezones

Numeric
^^^^^^^
-
- Bug in :func:`read_csv` with ``engine="pyarrow"`` causing rounding errors for large integers (:issue:`52505`)
-

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5 changes: 4 additions & 1 deletion pandas/io/parsers/arrow_parser_wrapper.py
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Expand Up @@ -223,5 +223,8 @@ def read(self) -> DataFrame:
elif using_pyarrow_string_dtype():
frame = table.to_pandas(types_mapper=arrow_string_types_mapper())
else:
frame = table.to_pandas()
if isinstance(self.kwds.get("dtype"), dict):
frame = table.to_pandas(types_mapper=self.kwds["dtype"].get)
else:
frame = table.to_pandas()
return self._finalize_pandas_output(frame)
17 changes: 17 additions & 0 deletions pandas/tests/io/parser/dtypes/test_dtypes_basic.py
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Expand Up @@ -558,3 +558,20 @@ def test_string_inference(all_parsers):
columns=pd.Index(["a", "b"], dtype=dtype),
)
tm.assert_frame_equal(result, expected)


def test_accurate_parsing_of_large_integers(all_parsers):
# GH#52505
data = """SYMBOL,MOMENT,ID,ID_DEAL
AAPL,20230301181139587,1925036343869802844,
AAPL,20230301181139587,2023552585717889863,2023552585717263358
NVDA,20230301181139587,2023552585717889863,2023552585717263359
AMC,20230301181139587,2023552585717889863,2023552585717263360
AMZN,20230301181139587,2023552585717889759,2023552585717263360
MSFT,20230301181139587,2023552585717889863,2023552585717263361
NVDA,20230301181139587,2023552585717889827,2023552585717263361"""
orders = pd.read_csv(StringIO(data), dtype={"ID_DEAL": pd.Int64Dtype()})
assert len(orders.loc[orders["ID_DEAL"] == 2023552585717263358, "ID_DEAL"]) == 1
assert len(orders.loc[orders["ID_DEAL"] == 2023552585717263359, "ID_DEAL"]) == 1
assert len(orders.loc[orders["ID_DEAL"] == 2023552585717263360, "ID_DEAL"]) == 2
assert len(orders.loc[orders["ID_DEAL"] == 2023552585717263361, "ID_DEAL"]) == 2