initial pass at PX auto-orientation

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

@@ -236,7 +236,7 @@ def area(
     labels={},
     color_discrete_sequence=None,
     color_discrete_map={},
-    orientation="v",
+    orientation=None,
     groupnorm=None,
     log_x=False,
     log_y=False,
@@ -256,9 +256,7 @@ def area(
     return make_figure(
         args=locals(),
         constructor=go.Scatter,
-        trace_patch=dict(
-            stackgroup=1, mode="lines", orientation=orientation, groupnorm=groupnorm
-        ),
+        trace_patch=dict(stackgroup=1, mode="lines", groupnorm=groupnorm),
     )
 
 
@@ -291,7 +289,7 @@ def bar(
     range_color=None,
     color_continuous_midpoint=None,
     opacity=None,
-    orientation="v",
+    orientation=None,
     barmode="relative",
     log_x=False,
     log_y=False,
@@ -335,7 +333,7 @@ def histogram(
     color_discrete_map={},
     marginal=None,
     opacity=None,
-    orientation="v",
+    orientation=None,
     barmode="relative",
     barnorm=None,
     histnorm=None,
@@ -361,13 +359,7 @@ def histogram(
         args=locals(),
         constructor=go.Histogram,
         trace_patch=dict(
-            orientation=orientation,
-            histnorm=histnorm,
-            histfunc=histfunc,
-            nbinsx=nbins if orientation == "v" else None,
-            nbinsy=None if orientation == "v" else nbins,
-            cumulative=dict(enabled=cumulative),
-            bingroup="x" if orientation == "v" else "y",
+            histnorm=histnorm, histfunc=histfunc, cumulative=dict(enabled=cumulative),
         ),
         layout_patch=dict(barmode=barmode, barnorm=barnorm),
     )
@@ -393,7 +385,7 @@ def violin(
     labels={},
     color_discrete_sequence=None,
     color_discrete_map={},
-    orientation="v",
+    orientation=None,
     violinmode="group",
     log_x=False,
     log_y=False,
@@ -414,12 +406,7 @@ def violin(
         args=locals(),
         constructor=go.Violin,
         trace_patch=dict(
-            orientation=orientation,
-            points=points,
-            box=dict(visible=box),
-            scalegroup=True,
-            x0=" ",
-            y0=" ",
+            points=points, box=dict(visible=box), scalegroup=True, x0=" ", y0=" ",
         ),
         layout_patch=dict(violinmode=violinmode),
     )
@@ -445,7 +432,7 @@ def box(
     labels={},
     color_discrete_sequence=None,
     color_discrete_map={},
-    orientation="v",
+    orientation=None,
     boxmode="group",
     log_x=False,
     log_y=False,
@@ -470,9 +457,7 @@ def box(
     return make_figure(
         args=locals(),
         constructor=go.Box,
-        trace_patch=dict(
-            orientation=orientation, boxpoints=points, notched=notched, x0=" ", y0=" "
-        ),
+        trace_patch=dict(boxpoints=points, notched=notched, x0=" ", y0=" "),
         layout_patch=dict(boxmode=boxmode),
     )
 
@@ -497,7 +482,7 @@ def strip(
     labels={},
     color_discrete_sequence=None,
     color_discrete_map={},
-    orientation="v",
+    orientation=None,
     stripmode="group",
     log_x=False,
     log_y=False,
@@ -516,7 +501,6 @@ def strip(
         args=locals(),
         constructor=go.Box,
         trace_patch=dict(
-            orientation=orientation,
             boxpoints="all",
             pointpos=0,
             hoveron="points",
@@ -1398,9 +1382,7 @@ def funnel(
     rectangular sector of a funnel.
     """
     return make_figure(
-        args=locals(),
-        constructor=go.Funnel,
-        trace_patch=dict(opacity=opacity, orientation=orientation),
+        args=locals(), constructor=go.Funnel, trace_patch=dict(opacity=opacity),
     )
 
 

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

@@ -92,6 +92,10 @@ def get_label(args, column):
         return column
 
 
+def _is_continuous(df, col_name):
+    return df[col_name].dtype.kind in "ifc"
+
+
 def get_decorated_label(args, column, role):
     label = get_label(args, column)
     if "histfunc" in args and (
@@ -188,7 +192,7 @@ def make_trace_kwargs(args, trace_spec, trace_data, mapping_labels, sizeref):
                 if ((not attr_value) or (name in attr_value))
                 and (
                     trace_spec.constructor != go.Parcoords
-                    or args["data_frame"][name].dtype.kind in "ifc"
+                    or _is_continuous(args["data_frame"], name)
                 )
                 and (
                     trace_spec.constructor != go.Parcats
@@ -1124,7 +1128,7 @@ def aggfunc_discrete(x):
     agg_f[count_colname] = "sum"
 
     if args["color"]:
-        if df[args["color"]].dtype.kind not in "ifc":
+        if not _is_continuous(df, args["color"]):
             aggfunc_color = aggfunc_discrete
             discrete_color = True
         elif not aggfunc_color:
@@ -1212,6 +1216,36 @@ def infer_config(args, constructor, trace_patch):
     if constructor in [go.Treemap, go.Sunburst] and args["path"] is not None:
         args = process_dataframe_hierarchy(args)
 
+    if "orientation" in args:
+        has_x = args["x"] is not None
+        has_y = args["y"] is not None
+        if args["orientation"] is None:
+            if constructor in [go.Histogram, go.Scatter]:
+                if has_y and not has_x:
+                    args["orientation"] = "h"
+            elif constructor in [go.Violin, go.Box, go.Bar, go.Funnel]:
+                if has_x and not has_y:
+                    args["orientation"] = "h"
+
+        if args["orientation"] is None and has_x and has_y:
+            x_is_continuous = _is_continuous(args["data_frame"], args["x"])
+            y_is_continuous = _is_continuous(args["data_frame"], args["y"])
+            if x_is_continuous and not y_is_continuous:
+                args["orientation"] = "h"
+            if y_is_continuous and not x_is_continuous:
+                args["orientation"] = "v"
+
+        if args["orientation"] is None:
+            args["orientation"] = "v"
+
+        if constructor == go.Histogram:
+            orientation = args["orientation"]
+            nbins = args["nbins"]
+            trace_patch["nbinsx"] = nbins if orientation == "v" else None
+            trace_patch["nbinsy"] = None if orientation == "v" else nbins
+            trace_patch["bingroup"] = "x" if orientation == "v" else "y"
+        trace_patch["orientation"] = args["orientation"]
+
     attrs = [k for k in attrables if k in args]
     grouped_attrs = []
 
@@ -1226,10 +1260,7 @@ def infer_config(args, constructor, trace_patch):
             if "color_discrete_sequence" not in args:
                 attrs.append("color")
             else:
-                if (
-                    args["color"]
-                    and args["data_frame"][args["color"]].dtype.kind in "ifc"
-                ):
+                if args["color"] and _is_continuous(args["data_frame"], args["color"]):
                     attrs.append("color")
                     args["color_is_continuous"] = True
                 elif constructor in [go.Sunburst, go.Treemap]: