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REF: simplify _try_cast #41705

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Merged
merged 3 commits into from
May 31, 2021
+11 −22
Merged

REF: simplify _try_cast #41705

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a0be123
REF: simplify _try_cast
jbrockmendel May 28, 2021
e1760f0
mypy fixup
jbrockmendel May 28, 2021
b35a6c6
Merge branch 'master' into ref-cast-3
jbrockmendel May 31, 2021
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28 changes: 8 additions & 20 deletions pandas/core/construction.py
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Original file line number Diff line number Diff line change
Expand Up @@ -17,10 +17,7 @@
import numpy.ma as ma

from pandas._libs import lib
from pandas._libs.tslibs import (
IncompatibleFrequency,
OutOfBoundsDatetime,
)
from pandas._libs.tslibs import IncompatibleFrequency
from pandas._typing import (
AnyArrayLike,
ArrayLike,
Expand Down Expand Up @@ -719,9 +716,7 @@ def _try_cast(
# while maybe_cast_to_datetime treats it as UTC
# see test_maybe_promote_any_numpy_dtype_with_datetimetz

# error: Incompatible return value type (got "Union[ExtensionArray,
# ndarray, List[Any]]", expected "Union[ExtensionArray, ndarray]")
return maybe_cast_to_datetime(arr, dtype) # type: ignore[return-value]
return maybe_cast_to_datetime(arr, dtype)
# TODO: copy?

array_type = dtype.construct_array_type()._from_sequence
Expand All @@ -734,6 +729,9 @@ def _try_cast(
return subarr
return ensure_wrapped_if_datetimelike(arr).astype(dtype, copy=copy)

elif dtype.kind in ["m", "M"]:
return maybe_cast_to_datetime(arr, dtype)

try:
# GH#15832: Check if we are requesting a numeric dtype and
# that we can convert the data to the requested dtype.
Expand All @@ -743,26 +741,16 @@ def _try_cast(
maybe_cast_to_integer_array(arr, dtype)
subarr = arr
else:
subarr = maybe_cast_to_datetime(arr, dtype)
if dtype is not None and dtype.kind == "M":
return subarr
subarr = arr

if not isinstance(subarr, ABCExtensionArray):
# 4 tests fail if we move this to a try/except/else; see
# test_constructor_compound_dtypes, test_constructor_cast_failure
# test_constructor_dict_cast2, test_loc_setitem_dtype
subarr = construct_1d_ndarray_preserving_na(subarr, dtype, copy=copy)

except OutOfBoundsDatetime:
# in case of out of bound datetime64 -> always raise
raise
except (ValueError, TypeError) as err:
if dtype is not None and raise_cast_failure:
raise
elif "Cannot cast" in str(err) or "cannot be converted to timedelta64" in str(
err
):
# via _disallow_mismatched_datetimelike
except (ValueError, TypeError):
if raise_cast_failure:
raise
else:
subarr = np.array(arr, dtype=object, copy=copy)
Expand Down
5 changes: 3 additions & 2 deletions pandas/core/dtypes/cast.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1579,7 +1579,7 @@ def try_timedelta(v: np.ndarray) -> np.ndarray:

def maybe_cast_to_datetime(
value: ExtensionArray | np.ndarray | list, dtype: DtypeObj | None
) -> ExtensionArray | np.ndarray | list:
) -> ExtensionArray | np.ndarray:
"""
try to cast the array/value to a datetimelike dtype, converting float
nan to iNaT
Expand Down Expand Up @@ -1705,7 +1705,8 @@ def maybe_cast_to_datetime(
"maybe_cast_to_datetime allows a list *only* if dtype is not None"
)

return value
# at this point we have converted or raised in all cases where we had a list
return cast(ArrayLike, value)


def sanitize_to_nanoseconds(values: np.ndarray, copy: bool = False) -> np.ndarray:
Expand Down