DEPR: is_extension_type (pandas-dev#29457)

Author: jbrockmendel

doc/source/whatsnew/v1.0.0.rst

@@ -213,7 +213,8 @@ Deprecations
 - ``Index.set_value`` has been deprecated. For a given index ``idx``, array ``arr``,
   value in ``idx`` of ``idx_val`` and a new value of ``val``, ``idx.set_value(arr, idx_val, val)``
   is equivalent to ``arr[idx.get_loc(idx_val)] = val``, which should be used instead (:issue:`28621`).
--
+- :func:`is_extension_type` is deprecated, :func:`is_extension_array_dtype` should be used instead (:issue:`29457`)
+
 
 .. _whatsnew_1000.prior_deprecations:
 

pandas/core/apply.py

@@ -7,7 +7,7 @@
 
 from pandas.core.dtypes.common import (
     is_dict_like,
-    is_extension_type,
+    is_extension_array_dtype,
     is_list_like,
     is_sequence,
 )
@@ -228,7 +228,7 @@ def apply_standard(self):
         # as demonstrated in gh-12244
         if (
             self.result_type in ["reduce", None]
-            and not self.dtypes.apply(is_extension_type).any()
+            and not self.dtypes.apply(is_extension_array_dtype).any()
             # Disallow complex_internals since libreduction shortcut
             #  cannot handle MultiIndex
             and not self.agg_axis._has_complex_internals

pandas/core/arrays/datetimes.py

@@ -31,7 +31,7 @@
     is_datetime64_ns_dtype,
     is_datetime64tz_dtype,
     is_dtype_equal,
-    is_extension_type,
+    is_extension_array_dtype,
     is_float_dtype,
     is_object_dtype,
     is_period_dtype,
@@ -2131,7 +2131,7 @@ def maybe_convert_dtype(data, copy):
         data = data.categories.take(data.codes, fill_value=NaT)._values
         copy = False
 
-    elif is_extension_type(data) and not is_datetime64tz_dtype(data):
+    elif is_extension_array_dtype(data) and not is_datetime64tz_dtype(data):
         # Includes categorical
         # TODO: We have no tests for these
         data = np.array(data, dtype=np.object_)

pandas/core/base.py

@@ -22,7 +22,6 @@
     is_datetime64_ns_dtype,
     is_datetime64tz_dtype,
     is_extension_array_dtype,
-    is_extension_type,
     is_list_like,
     is_object_dtype,
     is_scalar,
@@ -1267,7 +1266,7 @@ def _map_values(self, mapper, na_action=None):
                 # use the built in categorical series mapper which saves
                 # time by mapping the categories instead of all values
                 return self._values.map(mapper)
-            if is_extension_type(self.dtype):
+            if is_extension_array_dtype(self.dtype):
                 values = self._values
             else:
                 values = self.values
@@ -1278,7 +1277,8 @@ def _map_values(self, mapper, na_action=None):
             return new_values
 
         # we must convert to python types
-        if is_extension_type(self.dtype):
+        if is_extension_array_dtype(self.dtype) and hasattr(self._values, "map"):
+            # GH#23179 some EAs do not have `map`
             values = self._values
             if na_action is not None:
                 raise NotImplementedError

pandas/core/construction.py

@@ -27,7 +27,6 @@
     is_categorical_dtype,
     is_datetime64_ns_dtype,
     is_extension_array_dtype,
-    is_extension_type,
     is_float_dtype,
     is_integer_dtype,
     is_iterator,
@@ -527,7 +526,7 @@ def _try_cast(
             and not (is_iterator(subarr) or isinstance(subarr, np.ndarray))
         ):
             subarr = construct_1d_object_array_from_listlike(subarr)
-        elif not is_extension_type(subarr):
+        elif not is_extension_array_dtype(subarr):
             subarr = construct_1d_ndarray_preserving_na(subarr, dtype, copy=copy)
     except OutOfBoundsDatetime:
         # in case of out of bound datetime64 -> always raise

pandas/core/dtypes/cast.py

@@ -29,7 +29,6 @@
     is_datetime_or_timedelta_dtype,
     is_dtype_equal,
     is_extension_array_dtype,
-    is_extension_type,
     is_float,
     is_float_dtype,
     is_integer,
@@ -632,7 +631,7 @@ def infer_dtype_from_array(arr, pandas_dtype: bool = False):
     if not is_list_like(arr):
         arr = [arr]
 
-    if pandas_dtype and is_extension_type(arr):
+    if pandas_dtype and is_extension_array_dtype(arr):
         return arr.dtype, arr
 
     elif isinstance(arr, ABCSeries):
@@ -694,7 +693,7 @@ def maybe_upcast(values, fill_value=np.nan, dtype=None, copy=False):
         # We allow arbitrary fill values for object dtype
         raise ValueError("fill_value must be a scalar")
 
-    if is_extension_type(values):
+    if is_extension_array_dtype(values):
         if copy:
             values = values.copy()
     else:

pandas/core/dtypes/common.py

@@ -1625,6 +1625,8 @@ def is_extension_type(arr):
     """
     Check whether an array-like is of a pandas extension class instance.
 
+    .. deprecated:: 1.0.0
+
     Extension classes include categoricals, pandas sparse objects (i.e.
     classes represented within the pandas library and not ones external
     to it like scipy sparse matrices), and datetime-like arrays.
@@ -1667,6 +1669,12 @@ def is_extension_type(arr):
     >>> is_extension_type(s)
     True
     """
+    warnings.warn(
+        "'is_extension_type' is deprecated and will be removed in a future "
+        "version.  Use 'is_extension_array_dtype' instead.",
+        FutureWarning,
+        stacklevel=2,
+    )
 
     if is_categorical(arr):
         return True

pandas/core/frame.py

@@ -71,7 +71,6 @@
     is_dict_like,
     is_dtype_equal,
     is_extension_array_dtype,
-    is_extension_type,
     is_float_dtype,
     is_hashable,
     is_integer,
@@ -3658,7 +3657,7 @@ def reindexer(value):
             value = maybe_cast_to_datetime(value, infer_dtype)
 
         # return internal types directly
-        if is_extension_type(value) or is_extension_array_dtype(value):
+        if is_extension_array_dtype(value):
             return value
 
         # broadcast across multiple columns if necessary

pandas/core/internals/blocks.py

@@ -37,7 +37,6 @@
     is_datetime64tz_dtype,
     is_dtype_equal,
     is_extension_array_dtype,
-    is_extension_type,
     is_float_dtype,
     is_integer,
     is_integer_dtype,
@@ -2605,10 +2604,6 @@ def should_store(self, value):
                 value.dtype.type,
                 (np.integer, np.floating, np.complexfloating, np.datetime64, np.bool_),
             )
-            or
-            # TODO(ExtensionArray): remove is_extension_type
-            # when all extension arrays have been ported.
-            is_extension_type(value)
             or is_extension_array_dtype(value)
         )
 
@@ -3168,7 +3163,7 @@ def _putmask_preserve(nv, n):
     # change the dtype if needed
     dtype, _ = maybe_promote(n.dtype)
 
-    if is_extension_type(v.dtype) and is_object_dtype(dtype):
+    if is_extension_array_dtype(v.dtype) and is_object_dtype(dtype):
         v = v._internal_get_values(dtype)
     else:
         v = v.astype(dtype)

pandas/core/internals/managers.py

@@ -20,7 +20,6 @@
     _NS_DTYPE,
     is_datetimelike_v_numeric,
     is_extension_array_dtype,
-    is_extension_type,
     is_list_like,
     is_numeric_v_string_like,
     is_scalar,
@@ -1034,11 +1033,7 @@ def set(self, item, value):
         # FIXME: refactor, clearly separate broadcasting & zip-like assignment
         #        can prob also fix the various if tests for sparse/categorical
 
-        # TODO(EA): Remove an is_extension_ when all extension types satisfy
-        # the interface
-        value_is_extension_type = is_extension_type(value) or is_extension_array_dtype(
-            value
-        )
+        value_is_extension_type = is_extension_array_dtype(value)
 
         # categorical/sparse/datetimetz
         if value_is_extension_type: