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Drop duplicates #56957

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3883d07
DOC: Remove references to AxesSubPlot #56876
manlattan Jan 18, 2024
09b66ae
BUG: DataFrame.drop_duplicates method fails when a column with a list…
manlattan Jan 19, 2024
6e39e71
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Jan 19, 2024
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18 changes: 18 additions & 0 deletions pandas/core/frame.py
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Original file line number Diff line number Diff line change
Expand Up @@ -6721,6 +6721,24 @@ def drop_duplicates(
DataFrame or None
DataFrame with duplicates removed or None if ``inplace=True``.

Notes
--------
The methods :meth:`pandas.DataFrame.drop_duplicates` and :meth:`pandas.DataFrame.duplicated` rely on hashing.
Therefore, using a column with mutable objects, such as lists (are not hashable), in the subset parameter may result in unexpected behavior.

To handle mutable objects, convert the list column to a tuple before using it in the subset.

>>> df = pd.DataFrame([
... {'number': 1, 'item_ids': [1, 2, 3]},
... {'number': 1, 'item_ids': [1, 2, 3]},
... ])

>>> df['item_ids'] = df['item_ids'].apply(tuple)
>>> df.drop_duplicates(inplace=True)
>>> df['item_ids'] = df['item_ids'].apply(list)
number item_ids
0 1 [1, 2, 3]

See Also
--------
DataFrame.value_counts: Count unique combinations of columns.
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8 changes: 4 additions & 4 deletions pandas/plotting/_core.py
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Expand Up @@ -98,7 +98,7 @@ def hist_series(

Returns
-------
matplotlib.AxesSubplot
matplotlib.Axes
A histogram plot.

See Also
Expand Down Expand Up @@ -227,7 +227,7 @@ def hist_frame(

Returns
-------
matplotlib.AxesSubplot or numpy.ndarray of them
matplotlib.Axes or numpy.ndarray of them

See Also
--------
Expand Down Expand Up @@ -1374,7 +1374,7 @@ def hist(

Returns
-------
class:`matplotlib.AxesSubplot`
class:`matplotlib.Axes`
Return a histogram plot.

See Also
Expand Down Expand Up @@ -1794,7 +1794,7 @@ def hexbin(

Returns
-------
matplotlib.AxesSubplot
matplotlib.Axes
The matplotlib ``Axes`` on which the hexbin is plotted.

See Also
Expand Down