BUG: Fix Ability to set both color and style in pandas plotting

doc/source/whatsnew/v3.0.0.rst

@@ -632,6 +632,7 @@ Period
 Plotting
 ^^^^^^^^
 - Bug in :meth:`.DataFrameGroupBy.boxplot` failed when there were multiple groupings (:issue:`14701`)
+- Bug in :meth:`DataFrame.plot.line` raising ``ValueError`` when set both color and a ``dict`` style (:issue:`59461`)
 - 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`)
 

pandas/plotting/_matplotlib/core.py

@@ -451,7 +451,9 @@ def _validate_color_args(self, color, colormap):
             )
 
         if self.style is not None:
-            if is_list_like(self.style):
+            if isinstance(self.style, dict):
+                styles = [self.style[col] for col in self.columns if col in self.style]
+            elif is_list_like(self.style):
                 styles = self.style
             else:
                 styles = [self.style]

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 = 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)