Fix legend yerr (#40777)

Author: MarcoGorelli

doc/source/whatsnew/v1.3.0.rst

@@ -734,7 +734,9 @@ Plotting
 
 - Bug in :func:`scatter_matrix` raising when 2d ``ax`` argument passed (:issue:`16253`)
 - Prevent warnings when matplotlib's ``constrained_layout`` is enabled (:issue:`25261`)
--
+- Bug in :func:`DataFrame.plot` was showing the wrong colors in the legend if the function was called repeatedly and some calls used ``yerr`` while others didn't (partial fix of :issue:`39522`)
+- Bug in :func:`DataFrame.plot` was showing the wrong colors in the legend if the function was called repeatedly and some calls used ``secondary_y`` and others use ``legend=False`` (:issue:`40044`)
+
 
 Groupby/resample/rolling
 ^^^^^^^^^^^^^^^^^^^^^^^^

pandas/plotting/_matplotlib/core.py

@@ -596,7 +596,7 @@ def _append_legend_handles_labels(self, handle: Artist, label: str) -> None:
         self.legend_labels.append(label)
 
     def _make_legend(self):
-        ax, leg, handle = self._get_ax_legend_handle(self.axes[0])
+        ax, leg = self._get_ax_legend(self.axes[0])
 
         handles = []
         labels = []
@@ -606,7 +606,7 @@ def _make_legend(self):
             if leg is not None:
                 title = leg.get_title().get_text()
                 # Replace leg.LegendHandles because it misses marker info
-                handles.extend(handle)
+                handles = leg.legendHandles
                 labels = [x.get_text() for x in leg.get_texts()]
 
             if self.legend:
@@ -637,22 +637,20 @@ def _make_legend(self):
                 if ax.get_visible():
                     ax.legend(loc="best")
 
-    def _get_ax_legend_handle(self, ax: Axes):
+    def _get_ax_legend(self, ax: Axes):
         """
-        Take in axes and return ax, legend and handle under different scenarios
+        Take in axes and return ax and legend under different scenarios
         """
         leg = ax.get_legend()
 
-        # Get handle from axes
-        handle, _ = ax.get_legend_handles_labels()
         other_ax = getattr(ax, "left_ax", None) or getattr(ax, "right_ax", None)
         other_leg = None
         if other_ax is not None:
             other_leg = other_ax.get_legend()
         if leg is None and other_leg is not None:
             leg = other_leg
             ax = other_ax
-        return ax, leg, handle
+        return ax, leg
 
     @cache_readonly
     def plt(self):

pandas/tests/plotting/frame/test_frame.py

@@ -1163,127 +1163,6 @@ def test_plot_int_columns(self):
         df = DataFrame(np.random.randn(100, 4)).cumsum()
         _check_plot_works(df.plot, legend=True)
 
-    def test_df_legend_labels(self):
-        kinds = ["line", "bar", "barh", "kde", "area", "hist"]
-        df = DataFrame(np.random.rand(3, 3), columns=["a", "b", "c"])
-        df2 = DataFrame(np.random.rand(3, 3), columns=["d", "e", "f"])
-        df3 = DataFrame(np.random.rand(3, 3), columns=["g", "h", "i"])
-        df4 = DataFrame(np.random.rand(3, 3), columns=["j", "k", "l"])
-
-        for kind in kinds:
-
-            ax = df.plot(kind=kind, legend=True)
-            self._check_legend_labels(ax, labels=df.columns)
-
-            ax = df2.plot(kind=kind, legend=False, ax=ax)
-            self._check_legend_labels(ax, labels=df.columns)
-
-            ax = df3.plot(kind=kind, legend=True, ax=ax)
-            self._check_legend_labels(ax, labels=df.columns.union(df3.columns))
-
-            ax = df4.plot(kind=kind, legend="reverse", ax=ax)
-            expected = list(df.columns.union(df3.columns)) + list(reversed(df4.columns))
-            self._check_legend_labels(ax, labels=expected)
-
-        # Secondary Y
-        ax = df.plot(legend=True, secondary_y="b")
-        self._check_legend_labels(ax, labels=["a", "b (right)", "c"])
-        ax = df2.plot(legend=False, ax=ax)
-        self._check_legend_labels(ax, labels=["a", "b (right)", "c"])
-        ax = df3.plot(kind="bar", legend=True, secondary_y="h", ax=ax)
-        self._check_legend_labels(
-            ax, labels=["a", "b (right)", "c", "g", "h (right)", "i"]
-        )
-
-        # Time Series
-        ind = date_range("1/1/2014", periods=3)
-        df = DataFrame(np.random.randn(3, 3), columns=["a", "b", "c"], index=ind)
-        df2 = DataFrame(np.random.randn(3, 3), columns=["d", "e", "f"], index=ind)
-        df3 = DataFrame(np.random.randn(3, 3), columns=["g", "h", "i"], index=ind)
-        ax = df.plot(legend=True, secondary_y="b")
-        self._check_legend_labels(ax, labels=["a", "b (right)", "c"])
-        ax = df2.plot(legend=False, ax=ax)
-        self._check_legend_labels(ax, labels=["a", "b (right)", "c"])
-        ax = df3.plot(legend=True, ax=ax)
-        self._check_legend_labels(ax, labels=["a", "b (right)", "c", "g", "h", "i"])
-
-        # scatter
-        ax = df.plot.scatter(x="a", y="b", label="data1")
-        self._check_legend_labels(ax, labels=["data1"])
-        ax = df2.plot.scatter(x="d", y="e", legend=False, label="data2", ax=ax)
-        self._check_legend_labels(ax, labels=["data1"])
-        ax = df3.plot.scatter(x="g", y="h", label="data3", ax=ax)
-        self._check_legend_labels(ax, labels=["data1", "data3"])
-
-        # ensure label args pass through and
-        # index name does not mutate
-        # column names don't mutate
-        df5 = df.set_index("a")
-        ax = df5.plot(y="b")
-        self._check_legend_labels(ax, labels=["b"])
-        ax = df5.plot(y="b", label="LABEL_b")
-        self._check_legend_labels(ax, labels=["LABEL_b"])
-        self._check_text_labels(ax.xaxis.get_label(), "a")
-        ax = df5.plot(y="c", label="LABEL_c", ax=ax)
-        self._check_legend_labels(ax, labels=["LABEL_b", "LABEL_c"])
-        assert df5.columns.tolist() == ["b", "c"]
-
-    def test_missing_marker_multi_plots_on_same_ax(self):
-        # GH 18222
-        df = DataFrame(data=[[1, 1, 1, 1], [2, 2, 4, 8]], columns=["x", "r", "g", "b"])
-        fig, ax = self.plt.subplots(nrows=1, ncols=3)
-        # Left plot
-        df.plot(x="x", y="r", linewidth=0, marker="o", color="r", ax=ax[0])
-        df.plot(x="x", y="g", linewidth=1, marker="x", color="g", ax=ax[0])
-        df.plot(x="x", y="b", linewidth=1, marker="o", color="b", ax=ax[0])
-        self._check_legend_labels(ax[0], labels=["r", "g", "b"])
-        self._check_legend_marker(ax[0], expected_markers=["o", "x", "o"])
-        # Center plot
-        df.plot(x="x", y="b", linewidth=1, marker="o", color="b", ax=ax[1])
-        df.plot(x="x", y="r", linewidth=0, marker="o", color="r", ax=ax[1])
-        df.plot(x="x", y="g", linewidth=1, marker="x", color="g", ax=ax[1])
-        self._check_legend_labels(ax[1], labels=["b", "r", "g"])
-        self._check_legend_marker(ax[1], expected_markers=["o", "o", "x"])
-        # Right plot
-        df.plot(x="x", y="g", linewidth=1, marker="x", color="g", ax=ax[2])
-        df.plot(x="x", y="b", linewidth=1, marker="o", color="b", ax=ax[2])
-        df.plot(x="x", y="r", linewidth=0, marker="o", color="r", ax=ax[2])
-        self._check_legend_labels(ax[2], labels=["g", "b", "r"])
-        self._check_legend_marker(ax[2], expected_markers=["x", "o", "o"])
-
-    def test_legend_name(self):
-        multi = DataFrame(
-            np.random.randn(4, 4),
-            columns=[np.array(["a", "a", "b", "b"]), np.array(["x", "y", "x", "y"])],
-        )
-        multi.columns.names = ["group", "individual"]
-
-        ax = multi.plot()
-        leg_title = ax.legend_.get_title()
-        self._check_text_labels(leg_title, "group,individual")
-
-        df = DataFrame(np.random.randn(5, 5))
-        ax = df.plot(legend=True, ax=ax)
-        leg_title = ax.legend_.get_title()
-        self._check_text_labels(leg_title, "group,individual")
-
-        df.columns.name = "new"
-        ax = df.plot(legend=False, ax=ax)
-        leg_title = ax.legend_.get_title()
-        self._check_text_labels(leg_title, "group,individual")
-
-        ax = df.plot(legend=True, ax=ax)
-        leg_title = ax.legend_.get_title()
-        self._check_text_labels(leg_title, "new")
-
-    def test_no_legend(self):
-        kinds = ["line", "bar", "barh", "kde", "area", "hist"]
-        df = DataFrame(np.random.rand(3, 3), columns=["a", "b", "c"])
-
-        for kind in kinds:
-            ax = df.plot(kind=kind, legend=False)
-            self._check_legend_labels(ax, visible=False)
-
     def test_style_by_column(self):
         import matplotlib.pyplot as plt
 
@@ -2160,34 +2039,6 @@ def test_plot_no_numeric_data(self):
         with pytest.raises(TypeError, match="no numeric data to plot"):
             df.plot()
 
-    def test_missing_markers_legend(self):
-        # 14958
-        df = DataFrame(np.random.randn(8, 3), columns=["A", "B", "C"])
-        ax = df.plot(y=["A"], marker="x", linestyle="solid")
-        df.plot(y=["B"], marker="o", linestyle="dotted", ax=ax)
-        df.plot(y=["C"], marker="<", linestyle="dotted", ax=ax)
-
-        self._check_legend_labels(ax, labels=["A", "B", "C"])
-        self._check_legend_marker(ax, expected_markers=["x", "o", "<"])
-
-    def test_missing_markers_legend_using_style(self):
-        # 14563
-        df = DataFrame(
-            {
-                "A": [1, 2, 3, 4, 5, 6],
-                "B": [2, 4, 1, 3, 2, 4],
-                "C": [3, 3, 2, 6, 4, 2],
-                "X": [1, 2, 3, 4, 5, 6],
-            }
-        )
-
-        fig, ax = self.plt.subplots()
-        for kind in "ABC":
-            df.plot("X", kind, label=kind, ax=ax, style=".")
-
-        self._check_legend_labels(ax, labels=["A", "B", "C"])
-        self._check_legend_marker(ax, expected_markers=[".", ".", "."])
-
     @pytest.mark.parametrize(
         "index_name, old_label, new_label",
         [