primitive KDE implementation, matches though

Author: nicolaskruchten

packages/python/plotly/plotly/express/_chart_types.py

@@ -579,10 +579,7 @@ def kde(
     marginal=None,
     opacity=None,
     orientation=None,
-    kdenorm=None,  # TODO use this
-    kernel=None,  # TODO use this
     bw_method=None,  # TODO use this
-    bw_adjust=None,  # TODO use this
     log_x=False,
     log_y=False,
     range_x=None,

packages/python/plotly/plotly/express/_core.py

@@ -1319,7 +1319,7 @@ def build_dataframe(args, constructor):
     value_name = None  # will likely be "value" in wide_mode
     hist2d_types = [go.Histogram2d, go.Histogram2dContour]
     hist1d_orientation = (
-        constructor == go.Histogram or "ecdfmode" in args or "kernel" in args
+        constructor == go.Histogram or "ecdfmode" in args or "bw_method" in args
     )
     if constructor in cartesians:
         if wide_x and wide_y:
@@ -2106,6 +2106,19 @@ def make_figure(args, constructor, trace_patch=None, layout_patch=None):
                 elif args["ecdfnorm"] == "percent":
                     group[var] = 100.0 * group[var] / group_sum
 
+            if "bw_method" in args:
+                from scipy.stats import gaussian_kde
+
+                base = args["x"] if args["orientation"] == "v" else args["y"]
+                var = args["x"] if args["orientation"] == "h" else args["y"]
+                bw = args.get("bw_method")
+                group = group.sort_values(by=base)
+
+                kernel = gaussian_kde(
+                    dataset=group[base], weights=group[var], bw_method=bw
+                )
+                group[var] = kernel.evaluate(group[base])
+
             patch, fit_results = make_trace_kwargs(
                 args, trace_spec, group, mapping_labels.copy(), sizeref
             )

packages/python/plotly/plotly/express/_doc.py

@@ -591,10 +591,11 @@
         "If `'complementary'`, the CCDF is plotted such that values represent data above the point.",
         "If `'reversed'`, a variant of the CCDF is plotted such that values represent data at or above the point.",
     ],
-    kernel=["TODO"],  # kde
-    kdenorm=["TODO"],  # kde
-    bw_method=["TODO"],  # kde
-    bw_adjust=["TODO"],  # kde
+    bw_method=[
+        "str, scalar or callable (default `'scott'`)",
+        "If str, must be one of `'scott'` or `'silverman'`.",
+        "Passed to `scipy.stats.gaussian_kde`.",
+    ],
 )