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BUG: Preserve column names in DataFrame.from_records when nrows=0 #61143

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BUG: Preserve column names in DataFrame.from_records when nrows=0 #61143

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5dd7786
Fix from records() to preserve columns when nrows=0
kpvenkat47 Mar 18, 2025
cc21929
Update empty DataFrame initialization to preserve columns - Changed '…
kpvenkat47 Mar 18, 2025
e2fbceb
Updated PR #6114 based on review feedback
kpvenkat47 Mar 26, 2025
81ad960
Merge branch 'kpvenkat47-fix-from-records-nrows' into fix-empty-df-co…
kpvenkat47 Mar 26, 2025
5dcc1ac
All reviews are updated.Please check
kpvenkat47 Apr 1, 2025
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2 changes: 1 addition & 1 deletion pandas/core/frame.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2231,7 +2231,7 @@ def maybe_reorder(

if is_iterator(data):
if nrows == 0:
return cls()
return cls(columns=columns)

try:
first_row = next(data)
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8 changes: 8 additions & 0 deletions pandas/tests/frame/constructors/test_from_records.py
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Original file line number Diff line number Diff line change
Expand Up @@ -492,3 +492,11 @@ def test_from_records_structured_array(self):
expected_result = DataFrame(modified_data)

tm.assert_frame_equal(actual_result, expected_result)


def test_from_records_empty_iterator_with_preserve_columns(self):
# GH#61140
rows = []
result = DataFrame.from_records(iter(rows), columns=["col_1", "Col_2"], nrows=0)
expected = DataFrame([],columns=["col_1", "Col_2"])
tm.assert_frame_equal(result, expected)
2 changes: 1 addition & 1 deletion pandas/tests/frame/test_constructors.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2779,7 +2779,7 @@ def test_construction_nan_value_timedelta64_dtype(self):
["NaT", "0 days 00:00:00.000000001"], dtype="timedelta64[ns]"
)
tm.assert_frame_equal(result, expected)


class TestDataFrameConstructorIndexInference:
def test_frame_from_dict_of_series_overlapping_monthly_period_indexes(self):
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