update to comments

Author: jreback

doc/source/whatsnew/v0.23.0.txt

@@ -74,7 +74,7 @@ Rolling/Expanding.apply() accepts a ``raw`` keyword to pass a ``Series`` to the
 :func:`Series.expanding().apply() <pandas.core.window.Expanding.apply>`, and :func:`DataFrame.expanding().apply() <pandas.core.window.Expanding.apply>` have gained a ``raw=None`` parameter.
 This is similar to :func:`DataFame.apply`. This parameter, if ``True`` allows one to send a ``np.ndarray`` to the applied function. If ``False`` a ``Series`` will be passed. The
 default is ``None``, which preserves backward compatibility, so this will default to ``True``, sending an ``np.ndarray``.
-In a future version the default will be changed to ``False``, sending a ``Series``. (:issue:`5071`)
+In a future version the default will be changed to ``False``, sending a ``Series``. (:issue:`5071`, :issue:`20584`)
 
 .. ipython:: python
 
@@ -844,6 +844,7 @@ Other API Changes
 - :func:`DatetimeIndex.strftime` and :func:`PeriodIndex.strftime` now return an ``Index`` instead of a numpy array to be consistent with similar accessors (:issue:`20127`)
 - Constructing a Series from a list of length 1 no longer broadcasts this list when a longer index is specified (:issue:`19714`, :issue:`20391`).
 - :func:`DataFrame.to_dict` with ``orient='index'`` no longer casts int columns to float for a DataFrame with only int and float columns (:issue:`18580`)
+- A user-defined-function that is passed to :func:`Series.rolling().aggregate() <pandas.core.window.Rolling.aggregate>`, :func:`DataFrame.rolling().aggregate() <pandas.core.window.Rolling.aggregate>`, or its expanding cousines, will now *always* be passed a ``Series``, rather than an ``np.array``; ``.apply()`` only has the ``raw`` keyword, see :ref:`here <whatsnew_0230.enhancements.window_raw>`. This is consistent with the signatures of ``.aggregate()`` across pandas (:issue:`20584`)
 
 .. _whatsnew_0230.deprecations:
 
@@ -873,8 +874,7 @@ Deprecations
 - ``NDFrame.get_ftype_counts()`` is deprecated and will be removed in a future version (:issue:`18243`)
 - The ``convert_datetime64`` parameter in :func:`DataFrame.to_records` has been deprecated and will be removed in a future version. The NumPy bug motivating this parameter has been resolved. The default value for this parameter has also changed from ``True`` to ``None`` (:issue:`18160`).
 - :func:`Series.rolling().apply() <pandas.core.window.Rolling.apply>`, :func:`DataFrame.rolling().apply() <pandas.core.window.Rolling.apply>`,
-  :func:`Series.expanding().apply() <pandas.core.window.Expanding.apply>`, and :func:`DataFrame.expanding().apply() <pandas.core.window.Expanding.apply>` will show a ``FutureWarning`` if the new
-  ``raw`` parameter is not explicity passed (:issue:`20584`)
+  :func:`Series.expanding().apply() <pandas.core.window.Expanding.apply>`, and :func:`DataFrame.expanding().apply() <pandas.core.window.Expanding.apply>` have deprecated passing an ``np.array`` by default. One will need to pass the new ``raw`` parameter to be explicit about what is passed (:issue:`20584`)
 
 .. _whatsnew_0230.prior_deprecations:
 

pandas/core/generic.py

@@ -4292,6 +4292,8 @@ def pipe(self, func, *args, **kwargs):
     Notes
     -----
     `agg` is an alias for `aggregate`. Use the alias.
+
+    A passed user-defined-funtion will be passed a Series for evaluation.
     """)
 
     _shared_docs['transform'] = ("""

pandas/core/window.py

@@ -954,8 +954,8 @@ def count(self):
     Parameters
     ----------
     func : function
-        Must produce a single value from an ndarray input if raw=True
-        or a Series if raw=False
+        Must produce a single value from an ndarray input if ``raw=True``
+        or a Series if ``raw=False``
     raw : bool, default None
         * ``False`` : passes each row or column as a Series to the
           function.
@@ -965,7 +965,7 @@ def count(self):
           achieve much better performance.
 
         The raw parameter is required and will show a FutureWarning if
-        not passed. In the futures raw will default to False.
+        not passed. In the future raw will default to False.
 
         .. versionadded:: 0.23.0
 
@@ -984,10 +984,10 @@ def apply(self, func, raw=None, args=(), kwargs={}):
         # change to False in the future
         if raw is None:
             warnings.warn(
-                "raw defaults to False "
-                "meaning a Series will be passed to the "
-                "applied function. In the future raw will default to True "
-                "meaning a ndarray is passed to the "
+                "`raw` defaults to True "
+                "meaning a nndarray will be passed to the "
+                "applied function. In the future `raw` will default to False "
+                "meaning a Series is passed to the "
                 "applied function", FutureWarning, stacklevel=3)
             raw = True