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Added Datetime & Timedelta inference to array #24571

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34 changes: 25 additions & 9 deletions pandas/core/arrays/array_.py
Original file line number Diff line number Diff line change
Expand Up @@ -46,12 +46,14 @@ def array(data, # type: Sequence[object]

Currently, pandas will infer an extension dtype for sequences of

========================== ==================================
scalar type Array Type
========================== ==================================
* :class:`pandas.Interval` :class:`pandas.IntervalArray`
* :class:`pandas.Period` :class:`pandas.arrays.PeriodArray`
========================== ==================================
============================== =====================================
scalar type Array Type
============================= =====================================
* :class:`pandas.Interval` :class:`pandas.IntervalArray`
* :class:`pandas.Period` :class:`pandas.arrays.PeriodArray`
* :class:`datetime.datetime` :class:`pandas.arrays.DatetimeArray`
* :class:`datetime.timedelta` :class:`pandas.arrays.TimedeltaArray`
============================= =====================================

For all other cases, NumPy's usual inference rules will be used.

Expand All @@ -62,7 +64,8 @@ def array(data, # type: Sequence[object]

Returns
-------
array : ExtensionArray
ExtensionArray
The newly created array.

Raises
------
Expand Down Expand Up @@ -180,7 +183,9 @@ def array(data, # type: Sequence[object]
ValueError: Cannot pass scalar '1' to 'pandas.array'.
"""
from pandas.core.arrays import (
period_array, ExtensionArray, IntervalArray, PandasArray
period_array, ExtensionArray, IntervalArray, PandasArray,
DatetimeArrayMixin,
TimedeltaArrayMixin,
)
from pandas.core.internals.arrays import extract_array

Expand Down Expand Up @@ -220,7 +225,18 @@ def array(data, # type: Sequence[object]
# We choose to return an ndarray, rather than raising.
pass

# TODO(DatetimeArray): handle this type
elif inferred_dtype.startswith('datetime'):
# datetime, datetime64
try:
return DatetimeArrayMixin._from_sequence(data, copy=copy)
except ValueError:
# Mixture of timezones, fall back to PandasArray
pass

elif inferred_dtype.startswith('timedelta'):
# timedelta, timedelta64
return TimedeltaArrayMixin._from_sequence(data, copy=copy)

# TODO(BooleanArray): handle this type

result = PandasArray._from_sequence(data, dtype=dtype, copy=copy)
Expand Down
51 changes: 51 additions & 0 deletions pandas/tests/arrays/test_array.py
Original file line number Diff line number Diff line change
@@ -1,7 +1,9 @@
import datetime
import decimal

import numpy as np
import pytest
import pytz

from pandas.core.dtypes.dtypes import registry

Expand Down Expand Up @@ -89,11 +91,51 @@ def test_array_copy():
assert np.shares_memory(a, b._ndarray) is True


cet = pytz.timezone("CET")


@pytest.mark.parametrize('data, expected', [
# period
([pd.Period("2000", "D"), pd.Period("2001", "D")],
period_array(["2000", "2001"], freq="D")),

# interval
([pd.Interval(0, 1), pd.Interval(1, 2)],
pd.IntervalArray.from_breaks([0, 1, 2])),

# datetime
([pd.Timestamp('2000',), pd.Timestamp('2001')],
pd.arrays.DatetimeArray._from_sequence(['2000', '2001'])),

([datetime.datetime(2000, 1, 1), datetime.datetime(2001, 1, 1)],
pd.arrays.DatetimeArray._from_sequence(['2000', '2001'])),

(np.array([1, 2], dtype='M8[ns]'),
pd.arrays.DatetimeArray(np.array([1, 2], dtype='M8[ns]'))),

(np.array([1, 2], dtype='M8[us]'),
pd.arrays.DatetimeArray(np.array([1000, 2000], dtype='M8[ns]'))),

# datetimetz
([pd.Timestamp('2000', tz='CET'), pd.Timestamp('2001', tz='CET')],
pd.arrays.DatetimeArray._from_sequence(
['2000', '2001'], dtype=pd.DatetimeTZDtype(tz='CET'))),

([datetime.datetime(2000, 1, 1, tzinfo=cet),
datetime.datetime(2001, 1, 1, tzinfo=cet)],
pd.arrays.DatetimeArray._from_sequence(['2000', '2001'],
tz=cet)),

# timedelta
([pd.Timedelta('1H'), pd.Timedelta('2H')],
pd.arrays.TimedeltaArray._from_sequence(['1H', '2H'])),

(np.array([1, 2], dtype='m8[ns]'),
pd.arrays.TimedeltaArray(np.array([1, 2], dtype='m8[ns]'))),

(np.array([1, 2], dtype='m8[us]'),
pd.arrays.TimedeltaArray(np.array([1000, 2000], dtype='m8[ns]'))),

])
def test_array_inference(data, expected):
result = pd.array(data)
Expand All @@ -105,6 +147,15 @@ def test_array_inference(data, expected):
[pd.Period("2000", "D"), pd.Period("2001", "A")],
# mix of closed
[pd.Interval(0, 1, closed='left'), pd.Interval(1, 2, closed='right')],
# Mix of timezones
[pd.Timestamp("2000", tz="CET"), pd.Timestamp("2000", tz="UTC")],
# Mix of tz-aware and tz-naive
[pd.Timestamp("2000", tz="CET"), pd.Timestamp("2000")],
# GH-24569
pytest.param(
np.array([pd.Timestamp('2000'), pd.Timestamp('2000', tz='CET')]),
marks=pytest.mark.xfail(reason="bug in DTA._from_sequence")
),
])
def test_array_inference_fails(data):
result = pd.array(data)
Expand Down