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Merged
merged 4 commits into from
Aug 24, 2023
Merged

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

merged 4 commits into from
Aug 24, 2023

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kvn4
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@kvn4 kvn4 commented Aug 21, 2023

@kvn4 kvn4 changed the title mend Incorrect reading of CSV containing large integers Issue#52505 Aug 21, 2023
mroeschke
mroeschke reviewed Aug 22, 2023
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pandas/io/parsers/arrow_parser_wrapper.py Outdated
@@ -223,5 +223,10 @@ 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 self.kwds.get("dtype") is not None and issubclass(
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Can you use isinstance instead of issubclass?

mroeschke
mroeschke requested changes Aug 22, 2023
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This needs a tests and a whatsnew note in 2.2.0.rst

@mroeschke mroeschke added Bug IO CSV read_csv, to_csv Arrow pyarrow functionality labels Aug 22, 2023
mroeschke
mroeschke reviewed Aug 23, 2023
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doc/source/whatsnew/v2.2.0.rst Outdated
@@ -139,7 +139,7 @@ Timezones

Numeric
^^^^^^^
-
- Bug in :func:`_read`, pyarrow engine not defaulting to float64 causing precision errors when specifying a dtype; fixed by explicitly setting dtype if dtype not none and isinstance of dict (:issue:`52505`)
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Can you phrase this in terms of a public API?

mroeschke
mroeschke reviewed Aug 23, 2023
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pandas/tests/io/parser/dtypes/test_dtypes_basic.py Outdated

def test_accurate_parsing_of_large_integers(all_parsers):
# GH#52505
data = """SYMBOL,SYSTEM,TYPE,MOMENT,ID,ACTION,PRICE,VOLUME,ID_DEAL,PRICE_DEAL
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Can you reduce the unnecessary data for testing?

mroeschke
mroeschke reviewed Aug 23, 2023
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pandas/tests/io/parser/dtypes/test_dtypes_basic.py Outdated
MSFT,F,S,20230301181139587,2023552585717889863,2,75.00000,2,2023552585717263361,75.00000
NVDA,F,B,20230301181139587,2023552585717889827,2,75.00000,2,2023552585717263361,75.00000"""
orders = pd.read_csv(StringIO(data), dtype={"ID_DEAL": pd.Int64Dtype()})
print(len(orders.query("ID_DEAL==2023552585717263360", engine="python")))
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Suggested change
print(len(orders.query("ID_DEAL==2023552585717263360", engine="python")))

mroeschke
mroeschke reviewed Aug 23, 2023
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pandas/tests/io/parser/dtypes/test_dtypes_basic.py Outdated
orders = pd.read_csv(StringIO(data), dtype={"ID_DEAL": pd.Int64Dtype()})
print(len(orders.query("ID_DEAL==2023552585717263360", engine="python")))
tm.assert_equal(
len(orders.query("ID_DEAL==2023552585717263360", engine="python")), 2
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Can you not use query here?

Also a plain assert should be fine

mroeschke
mroeschke reviewed Aug 23, 2023
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doc/source/whatsnew/v2.2.0.rst Outdated
@@ -139,7 +139,7 @@ Timezones

Numeric
^^^^^^^
-
- Bug in :func:`_read`, pyarrow engine defaulting to float64 causing rounding errors for large integers; now processes input appropriately (:issue:`52505`)
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Suggested change
- Bug in :func:`_read`, pyarrow engine defaulting to float64 causing rounding errors for large integers; now processes input appropriately (:issue:`52505`)
- Bug in :func:`read_csv` with `engine="pyarrow"` causing rounding errors for large integers (:issue:`52505`)

mroeschke
mroeschke reviewed Aug 23, 2023
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pandas/io/parsers/arrow_parser_wrapper.py Outdated
Comment on lines 226 to 227
if self.kwds.get("dtype") is not None and isinstance(
type(self.kwds.get("dtype")), dict
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Suggested change
if self.kwds.get("dtype") is not None and isinstance(
type(self.kwds.get("dtype")), dict
if isinstance(self.kwds.get("dtype"), dict):

@mroeschke mroeschke added this to the 2.2 milestone Aug 24, 2023
@mroeschke mroeschke merged commit 766e2fc into pandas-dev:main Aug 24, 2023
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Thanks @kvn4

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BUG: incorrect reading of CSV containing large integers
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@kvn4 @mroeschke