DOC: update the pandas.DataFrame.plot.pie docstring

pandas/plotting/_core.py

@@ -3133,19 +3133,51 @@ def area(self, x=None, y=None, **kwds):
 
     def pie(self, y=None, **kwds):
         """
-        Pie chart
+        Generate a pie plot.
+
+        A pie plot is a proportional representation of the numerical data in a
+        column. This function wraps :meth:`matplotlib.pyplot.pie` for the
+        specified column. If no column reference is passed and
+        ``subplots=True`` a pie plot is drawn for each numerical column
+        independently.
 
         Parameters
         ----------
-        y : label or position, optional
-            Column to plot.
-        `**kwds` : optional
-            Additional keyword arguments are documented in
-            :meth:`pandas.DataFrame.plot`.
+        y : int or label, optional
+            Label or position of the column to plot.
+            If not provided, ``subplots=True`` argument must be passed.
+        **kwds
+            Keyword arguments to pass on to :meth:`pandas.DataFrame.plot`.
 
         Returns
         -------
-        axes : :class:`matplotlib.axes.Axes` or numpy.ndarray of them
+        axes : matplotlib.axes.Axes or np.ndarray of them.
+            A NumPy array is returned when `subplots` is True.
+
+        See Also
+        --------
+        Series.plot.pie : Generate a pie plot for a Series.
+        DataFrame.plot : Make plots of a DataFrame.
+
+        Examples
+        --------
+        In the example below we have a DataFrame with the information about
+        planet's mass and radius. We pass the the 'mass' column to the
+        pie function to get a pie plot.
+
+        .. plot::
+            :context: close-figs
+
+            >>> df = pd.DataFrame({'mass': [0.330, 4.87 , 5.97],
+            ...                    'radius': [2439.7, 6051.8, 6378.1]},
+            ...                   index=['Mercury', 'Venus', 'Earth'])
+            >>> plot = df.plot.pie(y='mass', figsize=(5, 5))
+
+        .. plot::
+            :context: close-figs
+
+            >>> plot = df.plot.pie(subplots=True, figsize=(6, 3))
+
         """
         return self(kind='pie', y=y, **kwds)