doc updates

Author: chris-b1

doc/source/timeseries.rst

@@ -1473,8 +1473,9 @@ Furthermore, you can also specify multiple aggregation functions for each column
    r.agg({'A' : ['sum','std'], 'B' : ['mean','std'] })
 
 
-If a ``DataFrame`` does not have a ``DatetimeIndex``, but instead you want
-to resample based on column in the frame, it can passed to the ``on`` keyword.
+If a ``DataFrame`` does not have a datetimelike index, but instead you want
+to resample based on datetimelike column in the frame, it can passed to the
+``on`` keyword.
 
 .. ipython:: python
 
@@ -1487,8 +1488,9 @@ to resample based on column in the frame, it can passed to the ``on`` keyword.
    df
    df.resample('M', on='date').sum()
 
-Similarly, if you instead want to resample by a level of ``MultiIndex``, its
-name or location can be passed to the ``level`` keyword.
+Similarly, if you instead want to resample by a datetimelike
+level of ``MultiIndex``, its name or location can be passed to the
+``level`` keyword.
 
 .. ipython:: python
 

doc/source/whatsnew/v0.19.0.txt

@@ -377,7 +377,7 @@ Other enhancements
 
     pd.Timestamp(year=2012, month=1, day=1, hour=8, minute=30)
 
-- the ``.resample()`` function now accepts a ``on=`` or ``level=`` parameter for resampling on a column or ``MultiIndex`` level (:issue:`13500`)
+- the ``.resample()`` function now accepts a ``on=`` or ``level=`` parameter for resampling on a datetimelike column or ``MultiIndex`` level (:issue:`13500`)
 
   .. ipython:: python
 

pandas/core/generic.py

@@ -4064,10 +4064,15 @@ def resample(self, rule, how=None, axis=0, fill_method=None, closed=None,
         on : string, optional
             For a DataFrame, column to use instead of index for resampling.
             Column must be datetime-like.
+
+            .. versionadded:: 0.19.0
+
         level : string or int, optional
             For a MultiIndex, level (name or number) to use for
             resampling.  Level must be datetime-like.
 
+            .. versionadded:: 0.19.0
+
         To learn more about the offset strings, please see `this link
         <http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases>`__.
 

pandas/core/groupby.py

@@ -247,7 +247,7 @@ def _get_grouper(self, obj):
                                                           sort=self.sort)
         return self.binner, self.grouper, self.obj
 
-    def _set_grouper(self, obj, sort=False, converter=None):
+    def _set_grouper(self, obj, sort=False):
         """
         given an object and the specifications, setup the internal grouper
         for this particular specification

pandas/tseries/resample.py

@@ -90,11 +90,10 @@ def __init__(self, obj, groupby=None, axis=0, kind=None, **kwargs):
         if self.groupby is not None:
             # upsampling and PeriodIndex resampling do not work
             # if resampling on a column or mi level
-            # this is state used to catch and raise an error
+            # this state used to catch and raise an error
             self.from_selection = (self.groupby.key is not None or
                                    self.groupby.level is not None)
-            obj = self._convert_obj(obj)
-            self.groupby._set_grouper(obj, sort=True)
+            self.groupby._set_grouper(self._convert_obj(obj), sort=True)
 
     def __unicode__(self):
         """ provide a nice str repr of our rolling object """