This fix enables you to preserve the datetime precision when using the melt method. #55270
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paulreece
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mroeschke
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Sep 25, 2023
doc/source/whatsnew/v2.1.1.rst
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| @@ -38,6 +38,7 @@ Bug fixes | |||
| - Fixed bug in :meth:`DataFrame.stack` with ``future_stack=True`` and columns a non-:class:`MultiIndex` consisting of tuples (:issue:`54948`) | |||
| - Fixed bug in :meth:`Series.dt.tz` with :class:`ArrowDtype` where a string was returned instead of a ``tzinfo`` object (:issue:`55003`) | |||
| - Fixed bug in :meth:`Series.pct_change` and :meth:`DataFrame.pct_change` showing unnecessary ``FutureWarning`` (:issue:`54981`) | |||
| - Fixed bug where using the melt method would not preserve the datetime (:issue:`55254`) | |||
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Can you move this to 2.2.0.rst?
mroeschke
reviewed
Sep 25, 2023
pandas/core/reshape/melt.py
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| @@ -134,7 +137,9 @@ def melt( | |||
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| mcolumns = id_vars + var_name + [value_name] | |||
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| if frame.shape[1] > 0: | |||
| if frame.shape[1] > 0 and not any( | |||
| isinstance(dt, DatetimeTZDtype) for dt in frame.dtypes.values | |||
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This may need to be more generic like
pandas/pandas/core/reshape/melt.py
Line 125 in e86ed37
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I ended up importing the types like so since pandas doesn't have a dtype method like numpy. Lmk if you had something else in mind.
pd_dtypes = (
CategoricalDtype,
DatetimeTZDtype,
ExtensionDtype,
IntervalDtype,
PeriodDtype,
SparseDtype,
)
if frame.shape[1] > 0 and not any(
isinstance(dt, pd_dtypes) for dt in frame.dtypes.values
)
paulreece
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mroeschke
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mroeschke
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Oct 3, 2023
mroeschke
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Oct 3, 2023
pandas/core/reshape/melt.py
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| @@ -134,7 +134,9 @@ def melt( | |||
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| mcolumns = id_vars + var_name + [value_name] | |||
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| if frame.shape[1] > 0: | |||
| if frame.shape[1] > 0 and not any( | |||
| not isinstance(dt, np.dtype) and dt._supports_2d for dt in frame.dtypes.values | |||
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Suggested change
| not isinstance(dt, np.dtype) and dt._supports_2d for dt in frame.dtypes.values | |
| not isinstance(dt, np.dtype) and dt._supports_2d for dt in frame.dtypes |
…e melt method. It fixes the issues raised in pandas-dev#55254.
mroeschke
approved these changes
Oct 3, 2023
|
Nice work @paulreece |
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doc/source/whatsnew/vX.X.X.rstfile if fixing a bug or adding a new feature.