BUG: Fix plotting set color style dict sametime

Author: AntiKnot

doc/source/whatsnew/v3.0.0.rst

@@ -634,6 +634,7 @@ Plotting
 - Bug in :meth:`.DataFrameGroupBy.boxplot` failed when there were multiple groupings (:issue:`14701`)
 - Bug in :meth:`DataFrame.plot` that causes a shift to the right when the frequency multiplier is greater than one. (:issue:`57587`)
 - Bug in :meth:`Series.plot` with ``kind="pie"`` with :class:`ArrowDtype` (:issue:`59192`)
+- Bug in :meth:`core._validate_color_args` raising ``ValueError`` when set both color and style in plt.plot.line (:issue:`59461`)
 
 Groupby/resample/rolling
 ^^^^^^^^^^^^^^^^^^^^^^^^

pandas/plotting/_matplotlib/core.py

@@ -455,6 +455,8 @@ def _validate_color_args(self, color, colormap):
                 styles = self.style
             else:
                 styles = [self.style]
+            if isinstance(self.style, dict):
+                styles = [self.style[col] for col in self.columns if col in self.style]
             # need only a single match
             for s in styles:
                 if _color_in_style(s):

pandas/tests/plotting/frame/test_frame_color.py

@@ -95,6 +95,18 @@ def test_color_and_marker(self, color, expected):
         assert all(i.get_linestyle() == "--" for i in ax.lines)
         assert all(i.get_marker() == "d" for i in ax.lines)
 
+    def test_color_and_style(self):
+        color = {"g": "black", "h": "brown"}
+        style = {"g": "-", "h": "--"}
+        expected_color = ["black", "brown"]
+        expected_style = ["-", "--"]
+        df = pd.DataFrame({"g": [1, 2], "h": [2, 3]}, index=[1, 2])
+        ax = df.plot.line(color=color, style=style)
+        color = [i.get_color() for i in ax.lines]
+        style = [i.get_linestyle() for i in ax.lines]
+        assert color == expected_color
+        assert style == expected_style
+
     def test_bar_colors(self):
         default_colors = _unpack_cycler(plt.rcParams)