BUG-26214 fix colors parameter in DataFrame.boxplot

doc/source/whatsnew/v0.25.0.rst

@@ -424,7 +424,7 @@ Plotting
 - Fixed bug where :class:`api.extensions.ExtensionArray` could not be used in matplotlib plotting (:issue:`25587`)
 - Bug in an error message in :meth:`DataFrame.plot`. Improved the error message if non-numerics are passed to :meth:`DataFrame.plot` (:issue:`25481`)
 - Bug in incorrect ticklabel positions when plotting an index that are non-numeric / non-datetime (:issue:`7612` :issue:`15912` :issue:`22334`)
--
+- Bug where :meth:`DataFrame.boxplot` would not accept a `color` parameter like `DataFrame.plot.box` (:issue:`26214`)
 -
 
 Groupby/Resample/Rolling

pandas/plotting/_core.py

@@ -2202,14 +2202,25 @@ def boxplot(data, column=None, by=None, ax=None, fontsize=None,
     def _get_colors():
         #  num_colors=3 is required as method maybe_color_bp takes the colors
         #  in positions 0 and 2.
-        return _get_standard_colors(color=kwds.get('color'), num_colors=3)
+        #  if colors not provided, use color 2 for medians and 0 for all else
+        result = _get_standard_colors(num_colors=3)
+        result = np.take(result, [0, 0, 2, 0])
+
+        colors = kwds.pop('color', None)
+        if colors and isinstance(colors, dict):
+            valid_keys = ['boxes', 'whiskers', 'medians', 'caps']
+            for i in range(4):
+                if valid_keys[i] in colors:
+                    result[i] = colors[valid_keys[i]]
+
+        return result
 
     def maybe_color_bp(bp):
-        if 'color' not in kwds:
-            from matplotlib.artist import setp
-            setp(bp['boxes'], color=colors[0], alpha=1)
-            setp(bp['whiskers'], color=colors[0], alpha=1)
-            setp(bp['medians'], color=colors[2], alpha=1)
+        from matplotlib.artist import setp
+        setp(bp['boxes'], color=colors[0], alpha=1)
+        setp(bp['whiskers'], color=colors[1], alpha=1)
+        setp(bp['medians'], color=colors[2], alpha=1)
+        setp(bp['caps'], color=colors[3], alpha=1)
 
     def plot_group(keys, values, ax):
         keys = [pprint_thing(x) for x in keys]

pandas/tests/plotting/test_boxplot_method.py

@@ -160,6 +160,24 @@ def test_fontsize(self):
         self._check_ticks_props(df.boxplot("a", fontsize=16),
                                 xlabelsize=16, ylabelsize=16)
 
+    @pytest.mark.parametrize('dict_colors, expected',
+                             [(dict(boxes='r',
+                                    whiskers='b',
+                                    medians='g',
+                                    caps='c'),
+                               dict(boxes='r',
+                                    whiskers='b',
+                                    medians='g',
+                                    caps='c')),
+                              (dict(boxes='r', invalid='b'), dict(boxes='r')),
+                              (102, dict())])
+    def test_color_kwd(self, dict_colors, expected):
+        # GH: 26214
+        df = DataFrame(random.rand(10, 2))
+        result = df.boxplot(color=dict_colors, return_type='dict')
+        for k, v in expected.items():
+            assert result[k][0].get_color() == v
+
 
 @td.skip_if_no_mpl
 class TestDataFrameGroupByPlots(TestPlotBase):