BUG: automatic color cycling when plotting Series without style or color argument (fixes #2816)

RELEASE.rst

@@ -76,13 +76,16 @@ pandas 0.11.0
     (e.g. np.array(datetime(2001,1,1,0,0))), w/o dtype being passed
   - 0-dim ndarrays with a passed dtype are handled correctly
     (e.g. np.array(0.,dtype='float32'))
+  - fix automatic color cycling when plotting consecutive timeseries
+    without color arguments (GH2816_)
 
 .. _GH622: https://github.com/pydata/pandas/issues/622
 .. _GH797: https://github.com/pydata/pandas/issues/797
 .. _GH2778: https://github.com/pydata/pandas/issues/2778
 .. _GH2793: https://github.com/pydata/pandas/issues/2793
 .. _GH2751: https://github.com/pydata/pandas/issues/2751
 .. _GH2747: https://github.com/pydata/pandas/issues/2747
+.. _GH2816: https://github.com/pydata/pandas/issues/2816
 
 pandas 0.10.1
 =============

pandas/tests/test_graphics.py

@@ -675,6 +675,18 @@ def test_time_series_plot_color_kwargs(self):
         line = ax.get_lines()[0]
         self.assert_(line.get_color() == 'green')
 
+    @slow
+    def test_time_series_plot_color_with_empty_kwargs(self):
+        import matplotlib.pyplot as plt
+
+        plt.close('all')
+        for i in range(3):
+            ax = Series(np.arange(12) + 1, index=date_range(
+            '1/1/2000', periods=12)).plot()
+
+        line_colors = [ l.get_color() for l in ax.get_lines() ]
+        self.assert_(line_colors == ['b', 'g', 'r'])
+
     @slow
     def test_grouped_hist(self):
         import matplotlib.pyplot as plt

pandas/tools/plotting.py

@@ -748,6 +748,8 @@ def _maybe_right_yaxis(self, ax):
 
         if (sec_true or has_sec) and not hasattr(ax, 'right_ax'):
             orig_ax, new_ax = ax, ax.twinx()
+            new_ax._get_lines.color_cycle = orig_ax._get_lines.color_cycle
+
             orig_ax.right_ax, new_ax.left_ax = new_ax, orig_ax
 
             if len(orig_ax.get_lines()) == 0:  # no data on left y
@@ -1063,13 +1065,12 @@ def _get_colors(self):
         cycle = plt.rcParams.get('axes.color_cycle', list('bgrcmyk'))
         if isinstance(cycle, basestring):
             cycle = list(cycle)
-        has_colors = 'color' in self.kwds
         colors = self.kwds.get('color', cycle)
         return colors
 
     def _maybe_add_color(self, colors, kwds, style, i):
-        kwds.pop('color', None)
-        if style is None or re.match('[a-z]+', style) is None:
+        has_color = 'color' in kwds
+        if has_color and (style is None or re.match('[a-z]+', style) is None):
             kwds['color'] = colors[i % len(colors)]
 
     def _make_plot(self):
@@ -2077,6 +2078,8 @@ def on_right(i):
     if on_right(0):
         orig_ax = ax0
         ax0 = ax0.twinx()
+        ax0._get_lines.color_cycle = orig_ax._get_lines.color_cycle
+
         orig_ax.get_yaxis().set_visible(False)
         orig_ax.right_ax = ax0
         ax0.left_ax = orig_ax
@@ -2094,6 +2097,8 @@ def on_right(i):
         if on_right(i):
             orig_ax = ax
             ax = ax.twinx()
+            ax._get_lines.color_cycle = orig_ax._get_lines.color_cycle
+
             orig_ax.get_yaxis().set_visible(False)
         axarr[i] = ax