CLN: remove _try_coerce_result altogether

pandas/core/groupby/ops.py

@@ -25,6 +25,7 @@
     is_categorical_dtype,
     is_complex_dtype,
     is_datetime64_any_dtype,
+    is_datetime64tz_dtype,
     is_integer_dtype,
     is_numeric_dtype,
     is_sparse,
@@ -451,6 +452,7 @@ def wrapper(*args, **kwargs):
 
     def _cython_operation(self, kind, values, how, axis, min_count=-1, **kwargs):
         assert kind in ["transform", "aggregate"]
+        orig_values = values
 
         # can we do this operation with our cython functions
         # if not raise NotImplementedError
@@ -475,6 +477,12 @@ def _cython_operation(self, kind, values, how, axis, min_count=-1, **kwargs):
                     "timedelta64 type does not support {} operations".format(how)
                 )
 
+        if is_datetime64tz_dtype(values.dtype):
+            # Cast to naive; we'll cast back at the end of the function
+            # TODO: possible need to reshape?  kludge can be avoided when
+            #  2D EA is allowed.
+            values = values.view("M8[ns]")
+
         arity = self._cython_arity.get(how, 1)
 
         vdim = values.ndim
@@ -581,6 +589,9 @@ def _cython_operation(self, kind, values, how, axis, min_count=-1, **kwargs):
         if swapped:
             result = result.swapaxes(0, axis)
 
+        if is_datetime64tz_dtype(orig_values.dtype):
+            result = type(orig_values)(result.astype(np.int64), dtype=orig_values.dtype)
+
         return result, names
 
     def aggregate(self, values, how, axis=0, min_count=-1):

pandas/core/internals/blocks.py

@@ -417,9 +417,6 @@ def fillna(self, value, limit=None, inplace=False, downcast=None):
         if self._can_hold_element(value):
             # equivalent: self._try_coerce_args(value) would not raise
             blocks = self.putmask(mask, value, inplace=inplace)
-            blocks = [
-                b.make_block(values=self._try_coerce_result(b.values)) for b in blocks
-            ]
             return self._maybe_downcast(blocks, downcast)
 
         # we can't process the value, but nothing to do
@@ -734,12 +731,7 @@ def _try_coerce_args(self, other):
 
         return other
 
-    def _try_coerce_result(self, result):
-        """ reverse of try_coerce_args """
-        return result
-
     def _try_coerce_and_cast_result(self, result, dtype=None):
-        result = self._try_coerce_result(result)
         result = self._try_cast_result(result, dtype=dtype)
         return result
 
@@ -1406,7 +1398,7 @@ def func(cond, values, other):
 
             try:
                 fastres = expressions.where(cond, values, other)
-                return self._try_coerce_result(fastres)
+                return fastres
             except Exception as detail:
                 if errors == "raise":
                     raise TypeError(
@@ -1692,7 +1684,6 @@ def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False)
         mask = _safe_reshape(mask, new_values.shape)
 
         new_values[mask] = new
-        new_values = self._try_coerce_result(new_values)
         return [self.make_block(values=new_values)]
 
     def _try_cast_result(self, result, dtype=None):
@@ -1870,20 +1861,6 @@ def _slice(self, slicer):
 
         return self.values[slicer]
 
-    def _try_cast_result(self, result, dtype=None):
-        """
-        if we have an operation that operates on for example floats
-        we want to try to cast back to our EA here if possible
-
-        result could be a 2-D numpy array, e.g. the result of
-        a numeric operation; but it must be shape (1, X) because
-        we by-definition operate on the ExtensionBlocks one-by-one
-
-        result could also be an EA Array itself, in which case it
-        is already a 1-D array
-        """
-        return result
-
     def formatting_values(self):
         # Deprecating the ability to override _formatting_values.
         # Do the warning here, it's only user in pandas, since we
@@ -2441,20 +2418,6 @@ def _try_coerce_args(self, other):
 
         return other
 
-    def _try_coerce_result(self, result):
-        """ reverse of try_coerce_args """
-        if isinstance(result, np.ndarray):
-            if result.ndim == 2:
-                # kludge for 2D blocks with 1D EAs
-                result = result[0, :]
-            if result.dtype == np.float64:
-                # needed for post-groupby.median
-                result = self._holder._from_sequence(
-                    result.astype(np.int64), freq=None, dtype=self.values.dtype
-                )
-
-        return result
-
     def diff(self, n, axis=0):
         """1st discrete difference
 
@@ -2615,10 +2578,6 @@ def _try_coerce_args(self, other):
 
         return other
 
-    def _try_coerce_result(self, result):
-        """ reverse of try_coerce_args / try_operate """
-        return result
-
     def should_store(self, value):
         return issubclass(
             value.dtype.type, np.timedelta64
@@ -3027,16 +2986,6 @@ def array_dtype(self):
         """
         return np.object_
 
-    def _try_coerce_result(self, result):
-        """ reverse of try_coerce_args """
-
-        # GH12564: CategoricalBlock is 1-dim only
-        # while returned results could be any dim
-        if (not is_categorical_dtype(result)) and isinstance(result, np.ndarray):
-            result = _block_shape(result, ndim=self.ndim)
-
-        return result
-
     def to_dense(self):
         # Categorical.get_values returns a DatetimeIndex for datetime
         # categories, so we can't simply use `np.asarray(self.values)` like

pandas/core/internals/managers.py

@@ -908,7 +908,7 @@ def fast_xs(self, loc):
             # Such assignment may incorrectly coerce NaT to None
             # result[blk.mgr_locs] = blk._slice((slice(None), loc))
             for i, rl in enumerate(blk.mgr_locs):
-                result[rl] = blk._try_coerce_result(blk.iget((i, loc)))
+                result[rl] = blk.iget((i, loc))
 
         if is_extension_array_dtype(dtype):
             result = dtype.construct_array_type()._from_sequence(result, dtype=dtype)