Clarify default window in rolling()

dstansby · dstansby · commit 255978dc5bb9 · 2017-11-08T18:34:04.000Z
diff --git a/pandas/core/window.py b/pandas/core/window.py
@@ -503,6 +503,7 @@ class Window(_Window):
     * ``general_gaussian`` (needs power, width)
     * ``slepian`` (needs width).
 
+    If ``win_type=None`` a boxcar window is used.
     """
 
     def validate(self):
