comments

Author: jreback

pandas/core/arrays/base.py

@@ -59,14 +59,14 @@ class ExtensionArray(object):
     * factorize / _values_for_factorize
     * argsort / _values_for_argsort
 
-    One can implement methods to handle array reductions.
-
-    * _reduce
-
     The remaining methods implemented on this class should be performant,
     as they only compose abstract methods. Still, a more efficient
     implementation may be available, and these methods can be overridden.
 
+    One can implement methods to handle array reductions.
+
+    * _reduce
+
     This class does not inherit from 'abc.ABCMeta' for performance reasons.
     Methods and properties required by the interface raise
     ``pandas.errors.AbstractMethodError`` and no ``register`` method is
@@ -691,7 +691,7 @@ def _reduce(self, name, skipna=True, **kwargs):
         skipna : bool, default True
             if True, skip NaN values
         kwargs : dict
-            ddof is the only supported kwarg
+            Additional keyword arguments passed to the reduction function
 
         Returns
         -------

pandas/core/arrays/integer.py

@@ -546,9 +546,9 @@ def _reduce(self, name, skipna=True, **kwargs):
         if name in ['any', 'all']:
             pass
 
-        # if we have a numeric op, provide coercion back to an integer
-        # type if possible
-        elif notna(result):
+        # if we have a preservable numeric op,
+        # provide coercion back to an integer type if possible
+        elif name in ['sum', 'min', 'max'] and notna(result):
             int_result = int(result)
             if int_result == result:
                 result = int_result

pandas/core/dtypes/common.py

@@ -1237,8 +1237,7 @@ def is_datetime_or_timedelta_dtype(arr_or_dtype):
     if arr_or_dtype is None:
         return False
     tipo = _get_dtype_type(arr_or_dtype)
-    return (issubclass(tipo, (np.datetime64, np.timedelta64)) or
-            is_datetime64tz_dtype(arr_or_dtype))
+    return issubclass(tipo, (np.datetime64, np.timedelta64))
 
 
 def _is_unorderable_exception(e):