REF: simplify try_cast (#33764)

Author: jbrockmendel

pandas/core/construction.py

@@ -27,7 +27,6 @@
  maybe_upcast,
 )
 from pandas.core.dtypes.common import (
- is_categorical_dtype,
  is_datetime64_ns_dtype,
  is_extension_array_dtype,
  is_float_dtype,
@@ -37,7 +36,7 @@
  is_object_dtype,
  is_timedelta64_ns_dtype,
 )
-from pandas.core.dtypes.dtypes import CategoricalDtype, ExtensionDtype, registry
+from pandas.core.dtypes.dtypes import ExtensionDtype, registry
 from pandas.core.dtypes.generic import (
  ABCExtensionArray,
  ABCIndexClass,
@@ -529,13 +528,23 @@ def _try_cast(
  if maybe_castable(arr) and not copy and dtype is None:
  return arr
 
+ if isinstance(dtype, ExtensionDtype) and dtype.kind != "M":
+ # create an extension array from its dtype
+ # DatetimeTZ case needs to go through maybe_cast_to_datetime
+ array_type = dtype.construct_array_type()._from_sequence
+ subarr = array_type(arr, dtype=dtype, copy=copy)
+ return subarr
+
  try:
  # GH#15832: Check if we are requesting a numeric dype and
  # that we can convert the data to the requested dtype.
  if is_integer_dtype(dtype):
- subarr = maybe_cast_to_integer_array(arr, dtype)
+ # this will raise if we have e.g. floats
+ maybe_cast_to_integer_array(arr, dtype)
+ subarr = arr
+ else:
+ subarr = maybe_cast_to_datetime(arr, dtype)
 
- subarr = maybe_cast_to_datetime(arr, dtype)
  # Take care in creating object arrays (but iterators are not
  # supported):
  if is_object_dtype(dtype) and (
@@ -549,19 +558,7 @@ def _try_cast(
  # in case of out of bound datetime64 -> always raise
  raise
  except (ValueError, TypeError):
- if is_categorical_dtype(dtype):
- # We *do* allow casting to categorical, since we know
- # that Categorical is the only array type for 'category'.
- dtype = cast(CategoricalDtype, dtype)
- subarr = dtype.construct_array_type()(
- arr, dtype.categories, ordered=dtype.ordered
- )
- elif is_extension_array_dtype(dtype):
- # create an extension array from its dtype
- dtype = cast(ExtensionDtype, dtype)
- array_type = dtype.construct_array_type()._from_sequence
- subarr = array_type(arr, dtype=dtype, copy=copy)
- elif dtype is not None and raise_cast_failure:
+ if dtype is not None and raise_cast_failure:
  raise
  else:
  subarr = np.array(arr, dtype=object, copy=copy)