TYP: plotting._matplotlib

pandas/_typing.py

@@ -326,3 +326,6 @@ def closed(self) -> bool:
 
 # quantile interpolation
 QuantileInterpolation = Literal["linear", "lower", "higher", "midpoint", "nearest"]
+
+# plotting
+PlottingOrientation = Literal["horizontal", "vertical"]

pandas/core/generic.py

@@ -5727,7 +5727,7 @@ def _check_inplace_setting(self, value) -> bool_t:
         return True
 
     @final
-    def _get_numeric_data(self):
+    def _get_numeric_data(self: NDFrameT) -> NDFrameT:
         return self._constructor(self._mgr.get_numeric_data()).__finalize__(self)
 
     @final
@@ -10954,7 +10954,8 @@ def mad(
 
         data = self._get_numeric_data()
         if axis == 0:
-            demeaned = data - data.mean(axis=0)
+            # error: Unsupported operand types for - ("NDFrame" and "float")
+            demeaned = data - data.mean(axis=0)  # type: ignore[operator]
         else:
             demeaned = data.sub(data.mean(axis=1), axis=0)
         return np.abs(demeaned).mean(axis=axis, skipna=skipna)

pandas/plotting/_core.py

@@ -1879,11 +1879,11 @@ def _get_plot_backend(backend: str | None = None):
     -----
     Modifies `_backends` with imported backend as a side effect.
     """
-    backend = backend or get_option("plotting.backend")
+    backend_str: str = backend or get_option("plotting.backend")
 
-    if backend in _backends:
-        return _backends[backend]
+    if backend_str in _backends:
+        return _backends[backend_str]
 
-    module = _load_backend(backend)
-    _backends[backend] = module
+    module = _load_backend(backend_str)
+    _backends[backend_str] = module
     return module

pandas/plotting/_matplotlib/boxplot.py

@@ -2,6 +2,7 @@
 
 from typing import (
     TYPE_CHECKING,
+    Literal,
     NamedTuple,
 )
 import warnings
@@ -34,7 +35,10 @@
 
 
 class BoxPlot(LinePlot):
-    _kind = "box"
+    @property
+    def _kind(self) -> Literal["box"]:
+        return "box"
+
     _layout_type = "horizontal"
 
     _valid_return_types = (None, "axes", "dict", "both")

pandas/plotting/_matplotlib/converter.py

@@ -574,6 +574,8 @@ def _daily_finder(vmin, vmax, freq: BaseOffset):
         Period(ordinal=int(vmin), freq=freq),
         Period(ordinal=int(vmax), freq=freq),
     )
+    assert isinstance(vmin, Period)
+    assert isinstance(vmax, Period)
     span = vmax.ordinal - vmin.ordinal + 1
     dates_ = period_range(start=vmin, end=vmax, freq=freq)
     # Initialize the output
@@ -1073,7 +1075,9 @@ def __call__(self, x, pos=0) -> str:
             fmt = self.formatdict.pop(x, "")
             if isinstance(fmt, np.bytes_):
                 fmt = fmt.decode("utf-8")
-            return Period(ordinal=int(x), freq=self.freq).strftime(fmt)
+            period = Period(ordinal=int(x), freq=self.freq)
+            assert isinstance(period, Period)
+            return period.strftime(fmt)
 
 
 class TimeSeries_TimedeltaFormatter(Formatter):

pandas/plotting/_matplotlib/core.py

@@ -1,17 +1,25 @@
 from __future__ import annotations
 
+from abc import (
+    ABC,
+    abstractmethod,
+)
 from typing import (
     TYPE_CHECKING,
     Hashable,
     Iterable,
+    Literal,
     Sequence,
 )
 import warnings
 
 from matplotlib.artist import Artist
 import numpy as np
 
-from pandas._typing import IndexLabel
+from pandas._typing import (
+    IndexLabel,
+    PlottingOrientation,
+)
 from pandas.errors import AbstractMethodError
 from pandas.util._decorators import cache_readonly
 
@@ -78,7 +86,7 @@ def _color_in_style(style: str) -> bool:
     return not set(BASE_COLORS).isdisjoint(style)
 
 
-class MPLPlot:
+class MPLPlot(ABC):
     """
     Base class for assembling a pandas plot using matplotlib
 
@@ -89,13 +97,17 @@ class MPLPlot:
     """
 
     @property
-    def _kind(self):
+    @abstractmethod
+    def _kind(self) -> str:
         """Specify kind str. Must be overridden in child class"""
         raise NotImplementedError
 
     _layout_type = "vertical"
     _default_rot = 0
-    orientation: str | None = None
+
+    @property
+    def orientation(self) -> str | None:
+        return None
 
     axes: np.ndarray  # of Axes objects
 
@@ -843,7 +855,9 @@ def _get_xticks(self, convert_period: bool = False):
 
     @classmethod
     @register_pandas_matplotlib_converters
-    def _plot(cls, ax: Axes, x, y, style=None, is_errorbar: bool = False, **kwds):
+    def _plot(
+        cls, ax: Axes, x, y: np.ndarray, style=None, is_errorbar: bool = False, **kwds
+    ):
         mask = isna(y)
         if mask.any():
             y = np.ma.array(y)
@@ -1101,7 +1115,7 @@ def _get_axes_layout(self) -> tuple[int, int]:
         return (len(y_set), len(x_set))
 
 
-class PlanePlot(MPLPlot):
+class PlanePlot(MPLPlot, ABC):
     """
     Abstract class for plotting on plane, currently scatter and hexbin.
     """
@@ -1159,7 +1173,9 @@ def _plot_colorbar(self, ax: Axes, **kwds):
 
 
 class ScatterPlot(PlanePlot):
-    _kind = "scatter"
+    @property
+    def _kind(self) -> Literal["scatter"]:
+        return "scatter"
 
     def __init__(self, data, x, y, s=None, c=None, **kwargs) -> None:
         if s is None:
@@ -1247,7 +1263,9 @@ def _make_plot(self):
 
 
 class HexBinPlot(PlanePlot):
-    _kind = "hexbin"
+    @property
+    def _kind(self) -> Literal["hexbin"]:
+        return "hexbin"
 
     def __init__(self, data, x, y, C=None, **kwargs) -> None:
         super().__init__(data, x, y, **kwargs)
@@ -1277,9 +1295,15 @@ def _make_legend(self):
 
 
 class LinePlot(MPLPlot):
-    _kind = "line"
     _default_rot = 0
-    orientation = "vertical"
+
+    @property
+    def orientation(self) -> PlottingOrientation:
+        return "vertical"
+
+    @property
+    def _kind(self) -> Literal["line", "area", "hist", "kde", "box"]:
+        return "line"
 
     def __init__(self, data, **kwargs) -> None:
         from pandas.plotting import plot_params
@@ -1363,8 +1387,7 @@ def _plot(  # type: ignore[override]
         cls._update_stacker(ax, stacking_id, y)
         return lines
 
-    @classmethod
-    def _ts_plot(cls, ax: Axes, x, data, style=None, **kwds):
+    def _ts_plot(self, ax: Axes, x, data, style=None, **kwds):
         # accept x to be consistent with normal plot func,
         # x is not passed to tsplot as it uses data.index as x coordinate
         # column_num must be in kwds for stacking purpose
@@ -1377,9 +1400,9 @@ def _ts_plot(cls, ax: Axes, x, data, style=None, **kwds):
             decorate_axes(ax.left_ax, freq, kwds)
         if hasattr(ax, "right_ax"):
             decorate_axes(ax.right_ax, freq, kwds)
-        ax._plot_data.append((data, cls._kind, kwds))
+        ax._plot_data.append((data, self._kind, kwds))
 
-        lines = cls._plot(ax, data.index, data.values, style=style, **kwds)
+        lines = self._plot(ax, data.index, data.values, style=style, **kwds)
         # set date formatter, locators and rescale limits
         format_dateaxis(ax, ax.freq, data.index)
         return lines
@@ -1471,7 +1494,9 @@ def get_label(i):
 
 
 class AreaPlot(LinePlot):
-    _kind = "area"
+    @property
+    def _kind(self) -> Literal["area"]:
+        return "area"
 
     def __init__(self, data, **kwargs) -> None:
         kwargs.setdefault("stacked", True)
@@ -1544,9 +1569,15 @@ def _post_plot_logic(self, ax: Axes, data):
 
 
 class BarPlot(MPLPlot):
-    _kind = "bar"
+    @property
+    def _kind(self) -> Literal["bar", "barh"]:
+        return "bar"
+
     _default_rot = 90
-    orientation = "vertical"
+
+    @property
+    def orientation(self) -> PlottingOrientation:
+        return "vertical"
 
     def __init__(self, data, **kwargs) -> None:
         # we have to treat a series differently than a
@@ -1698,9 +1729,15 @@ def _decorate_ticks(self, ax: Axes, name, ticklabels, start_edge, end_edge):
 
 
 class BarhPlot(BarPlot):
-    _kind = "barh"
+    @property
+    def _kind(self) -> Literal["barh"]:
+        return "barh"
+
     _default_rot = 0
-    orientation = "horizontal"
+
+    @property
+    def orientation(self) -> Literal["horizontal"]:
+        return "horizontal"
 
     @property
     def _start_base(self):
@@ -1727,7 +1764,10 @@ def _decorate_ticks(self, ax: Axes, name, ticklabels, start_edge, end_edge):
 
 
 class PiePlot(MPLPlot):
-    _kind = "pie"
+    @property
+    def _kind(self) -> Literal["pie"]:
+        return "pie"
+
     _layout_type = "horizontal"
 
     def __init__(self, data, kind=None, **kwargs) -> None:

pandas/plotting/_matplotlib/hist.py

@@ -1,9 +1,14 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING
+from typing import (
+    TYPE_CHECKING,
+    Literal,
+)
 
 import numpy as np
 
+from pandas._typing import PlottingOrientation
+
 from pandas.core.dtypes.common import (
     is_integer,
     is_list_like,
@@ -40,7 +45,9 @@
 
 
 class HistPlot(LinePlot):
-    _kind = "hist"
+    @property
+    def _kind(self) -> Literal["hist", "kde"]:
+        return "hist"
 
     def __init__(self, data, bins=10, bottom=0, **kwargs) -> None:
         self.bins = bins  # use mpl default
@@ -64,8 +71,8 @@ def _args_adjust(self):
 
     def _calculate_bins(self, data: DataFrame) -> np.ndarray:
         """Calculate bins given data"""
-        values = data._convert(datetime=True)._get_numeric_data()
-        values = np.ravel(values)
+        nd_values = data._convert(datetime=True)._get_numeric_data()
+        values = np.ravel(nd_values)
         values = values[~isna(values)]
 
         hist, bins = np.histogram(
@@ -159,16 +166,21 @@ def _post_plot_logic(self, ax: Axes, data):
             ax.set_ylabel("Frequency")
 
     @property
-    def orientation(self):
+    def orientation(self) -> PlottingOrientation:
         if self.kwds.get("orientation", None) == "horizontal":
             return "horizontal"
         else:
             return "vertical"
 
 
 class KdePlot(HistPlot):
-    _kind = "kde"
-    orientation = "vertical"
+    @property
+    def _kind(self) -> Literal["kde"]:
+        return "kde"
+
+    @property
+    def orientation(self) -> Literal["vertical"]:
+        return "vertical"
 
     def __init__(self, data, bw_method=None, ind=None, **kwargs) -> None:
         MPLPlot.__init__(self, data, **kwargs)

pandas/plotting/_matplotlib/style.py

@@ -143,8 +143,8 @@ def _get_colors_from_colormap(
     num_colors: int,
 ) -> list[Color]:
     """Get colors from colormap."""
-    colormap = _get_cmap_instance(colormap)
-    return [colormap(num) for num in np.linspace(0, 1, num=num_colors)]
+    cmap = _get_cmap_instance(colormap)
+    return [cmap(num) for num in np.linspace(0, 1, num=num_colors)]
 
 
 def _get_cmap_instance(colormap: str | Colormap) -> Colormap:

pandas/plotting/_matplotlib/timeseries.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from datetime import timedelta
 import functools
 from typing import (
     TYPE_CHECKING,
@@ -185,11 +186,10 @@ def _get_ax_freq(ax: Axes):
     return ax_freq
 
 
-def _get_period_alias(freq) -> str | None:
+def _get_period_alias(freq: timedelta | BaseOffset | str) -> str | None:
     freqstr = to_offset(freq).rule_code
 
-    freq = get_period_alias(freqstr)
-    return freq
+    return get_period_alias(freqstr)
 
 
 def _get_freq(ax: Axes, series: Series):
@@ -235,7 +235,9 @@ def use_dynamic_x(ax: Axes, data: DataFrame | Series) -> bool:
         x = data.index
         if base <= FreqGroup.FR_DAY.value:
             return x[:1].is_normalized
-        return Period(x[0], freq_str).to_timestamp().tz_localize(x.tz) == x[0]
+        period = Period(x[0], freq_str)
+        assert isinstance(period, Period)
+        return period.to_timestamp().tz_localize(x.tz) == x[0]
     return True
 
 

pandas/plotting/_matplotlib/tools.py

@@ -83,7 +83,11 @@ def table(
     return table
 
 
-def _get_layout(nplots: int, layout=None, layout_type: str = "box") -> tuple[int, int]:
+def _get_layout(
+    nplots: int,
+    layout: tuple[int, int] | None = None,
+    layout_type: str = "box",
+) -> tuple[int, int]:
     if layout is not None:
         if not isinstance(layout, (tuple, list)) or len(layout) != 2:
             raise ValueError("Layout must be a tuple of (rows, columns)")