Add pie plots (#8)

Author: FBumann

xarray_plotly/accessor.py

@@ -33,7 +33,7 @@ class DataArrayPlotlyAccessor:
         ```
     """
 
-    __all__: ClassVar = ["line", "bar", "area", "scatter", "box", "imshow"]
+    __all__: ClassVar = ["line", "bar", "area", "scatter", "box", "imshow", "pie"]
 
     def __init__(self, darray: DataArray) -> None:
         self._da = darray
@@ -274,6 +274,38 @@ def imshow(
             **px_kwargs,
         )
 
+    def pie(
+        self,
+        *,
+        names: SlotValue = auto,
+        color: SlotValue = None,
+        facet_col: SlotValue = auto,
+        facet_row: SlotValue = auto,
+        **px_kwargs: Any,
+    ) -> go.Figure:
+        """Create an interactive pie chart.
+
+        Slot order: names -> facet_col -> facet_row
+
+        Args:
+            names: Dimension for pie slice names/categories. Default: first dimension.
+            color: Dimension for color grouping. Default: None (uses names).
+            facet_col: Dimension for subplot columns. Default: second dimension.
+            facet_row: Dimension for subplot rows. Default: third dimension.
+            **px_kwargs: Additional arguments passed to `plotly.express.pie()`.
+
+        Returns:
+            Interactive Plotly Figure.
+        """
+        return plotting.pie(
+            self._da,
+            names=names,
+            color=color,
+            facet_col=facet_col,
+            facet_row=facet_row,
+            **px_kwargs,
+        )
+
 
 class DatasetPlotlyAccessor:
     """Plotly Express plotting accessor for xarray Dataset.
@@ -307,7 +339,7 @@ class DatasetPlotlyAccessor:
         ```
     """
 
-    __all__: ClassVar = ["line", "bar", "area", "scatter", "box"]
+    __all__: ClassVar = ["line", "bar", "area", "scatter", "box", "pie"]
 
     def __init__(self, dataset: Dataset) -> None:
         self._ds = dataset
@@ -519,3 +551,36 @@ def box(
             animation_frame=animation_frame,
             **px_kwargs,
         )
+
+    def pie(
+        self,
+        var: str | None = None,
+        *,
+        names: SlotValue = auto,
+        color: SlotValue = None,
+        facet_col: SlotValue = auto,
+        facet_row: SlotValue = auto,
+        **px_kwargs: Any,
+    ) -> go.Figure:
+        """Create an interactive pie chart.
+
+        Args:
+            var: Variable to plot. If None, plots all variables with "variable" dimension.
+            names: Dimension for pie slice names/categories.
+            color: Dimension for color grouping.
+            facet_col: Dimension for subplot columns.
+            facet_row: Dimension for subplot rows.
+            **px_kwargs: Additional arguments passed to `plotly.express.pie()`.
+
+        Returns:
+            Interactive Plotly Figure.
+        """
+        da = self._get_dataarray(var)
+        return plotting.pie(
+            da,
+            names=names,
+            color=color,
+            facet_col=facet_col,
+            facet_row=facet_row,
+            **px_kwargs,
+        )

xarray_plotly/config.py

@@ -44,6 +44,7 @@
     ),
     "imshow": ("y", "x", "facet_col", "animation_frame"),
     "box": ("x", "color", "facet_col", "facet_row", "animation_frame"),
+    "pie": ("names", "facet_col", "facet_row"),
 }
 
 

xarray_plotly/plotting.py

@@ -446,3 +446,64 @@ def imshow(
         animation_frame=slots.get("animation_frame"),
         **px_kwargs,
     )
+
+
+def pie(
+    darray: DataArray,
+    *,
+    names: SlotValue = auto,
+    color: SlotValue = None,
+    facet_col: SlotValue = auto,
+    facet_row: SlotValue = auto,
+    **px_kwargs: Any,
+) -> go.Figure:
+    """
+    Create an interactive pie chart from a DataArray.
+
+    The values are the DataArray values. Dimensions fill slots in order:
+    names -> facet_col -> facet_row
+
+    Parameters
+    ----------
+    darray
+        The DataArray to plot.
+    names
+        Dimension for pie slice names/categories. Default: first dimension.
+    color
+        Dimension for color grouping. Default: None (uses names).
+    facet_col
+        Dimension for subplot columns. Default: second dimension.
+    facet_row
+        Dimension for subplot rows. Default: third dimension.
+    **px_kwargs
+        Additional arguments passed to `plotly.express.pie()`.
+
+    Returns
+    -------
+    plotly.graph_objects.Figure
+    """
+    slots = assign_slots(
+        list(darray.dims),
+        "pie",
+        names=names,
+        facet_col=facet_col,
+        facet_row=facet_row,
+    )
+
+    df = to_dataframe(darray)
+    value_col = get_value_col(darray)
+    labels = {**build_labels(darray, slots, value_col), **px_kwargs.pop("labels", {})}
+
+    # Use names dimension for color if not explicitly set
+    color_col = color if color is not None else slots.get("names")
+
+    return px.pie(
+        df,
+        names=slots.get("names"),
+        values=value_col,
+        color=color_col,
+        facet_col=slots.get("facet_col"),
+        facet_row=slots.get("facet_row"),
+        labels=labels,
+        **px_kwargs,
+    )