Title check checks for subplot length if specified

pandas-dev · mroeschke · May 7, 2025 · Mar 21, 2025 · Mar 21, 2025 · Mar 30, 2025
commit 2e8fc9ac2d17783b63a9a39ca8d3ee9453e330f1
diff --git a/pandas/plotting/_matplotlib/core.py b/pandas/plotting/_matplotlib/core.py
@@ -802,7 +802,16 @@ def _adorn_subplots(self, fig: Figure) -> None:
        if self.title:
            if self.subplots:
                if is_list_like(self.title):
-                    if len(self.title) != self.nseries:
+                    if type(self.subplots) != bool:
+                        if len(self.subplots) != len(self.title):
+                            raise ValueError(
+                                "The length of `title` must equal the number "
+                                "of subplots if `title` of type `list` "
+                                "and subplots is iterable.\n"
+                                f"length of title = {len(self.title)}\n"
+                                f"number of subplots = {len(self.subplots)}"
+                            )
+                    elif len(self.title) != self.nseries:
                        raise ValueError(
                            "The length of `title` must equal the number "
                            "of columns if using `title` of type `list` "

diff --git a/pandas/tests/plotting/test_misc.py b/pandas/tests/plotting/test_misc.py
@@ -696,8 +696,9 @@ def test_plot_bar_label_count_expected_fail():
    )
    with pytest.raises(
        ValueError,
-        match="The length of `title` must equal the number of columns "
-        "if using `title` of type `list` and `subplots=True`.",
+        match="The length of `title` must equal the number "
+        "of subplots if `title` of type `list` "
+        "and subplots is iterable.\n",
    ):
        df.plot(
            subplots=[("A", "B")],