ability to show markers on lines

Author: nicolaskruchten

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

@@ -202,7 +202,9 @@ def density_heatmap(
         z=[
             "For `density_heatmap` and `density_contour` these values are used as the inputs to `histfunc`.",
         ],
-        histfunc=["The arguments to this function are the values of `z`.",],
+        histfunc=[
+            "The arguments to this function are the values of `z`.",
+        ],
     ),
 )
 
@@ -214,6 +216,7 @@ def line(
     line_group=None,
     color=None,
     line_dash=None,
+    symbol=None,
     hover_name=None,
     hover_data=None,
     custom_data=None,
@@ -236,6 +239,9 @@ def line(
     color_discrete_map=None,
     line_dash_sequence=None,
     line_dash_map=None,
+    symbol_sequence=None,
+    symbol_map=None,
+    markers=False,
     log_x=False,
     log_y=False,
     range_x=None,
@@ -263,6 +269,7 @@ def area(
     y=None,
     line_group=None,
     color=None,
+    symbol=None,
     hover_name=None,
     hover_data=None,
     custom_data=None,
@@ -278,6 +285,9 @@ def area(
     labels=None,
     color_discrete_sequence=None,
     color_discrete_map=None,
+    symbol_sequence=None,
+    symbol_map=None,
+    markers=False,
     orientation=None,
     groupnorm=None,
     log_x=False,
@@ -459,7 +469,9 @@ def histogram(
         args=locals(),
         constructor=go.Histogram,
         trace_patch=dict(
-            histnorm=histnorm, histfunc=histfunc, cumulative=dict(enabled=cumulative),
+            histnorm=histnorm,
+            histfunc=histfunc,
+            cumulative=dict(enabled=cumulative),
         ),
         layout_patch=dict(barmode=barmode, barnorm=barnorm),
     )
@@ -519,7 +531,11 @@ def violin(
         args=locals(),
         constructor=go.Violin,
         trace_patch=dict(
-            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),
     )
@@ -694,6 +710,7 @@ def line_3d(
     line_dash=None,
     text=None,
     line_group=None,
+    symbol=None,
     hover_name=None,
     hover_data=None,
     custom_data=None,
@@ -711,6 +728,9 @@ def line_3d(
     color_discrete_map=None,
     line_dash_sequence=None,
     line_dash_map=None,
+    symbol_sequence=None,
+    symbol_map=None,
+    markers=False,
     log_x=False,
     log_y=False,
     log_z=False,
@@ -780,6 +800,7 @@ def line_ternary(
     color=None,
     line_dash=None,
     line_group=None,
+    symbol=None,
     hover_name=None,
     hover_data=None,
     custom_data=None,
@@ -792,6 +813,9 @@ def line_ternary(
     color_discrete_map=None,
     line_dash_sequence=None,
     line_dash_map=None,
+    symbol_sequence=None,
+    symbol_map=None,
+    markers=False,
     line_shape=None,
     title=None,
     template=None,
@@ -864,6 +888,7 @@ def line_polar(
     custom_data=None,
     line_group=None,
     text=None,
+    symbol=None,
     animation_frame=None,
     animation_group=None,
     category_orders=None,
@@ -872,6 +897,9 @@ def line_polar(
     color_discrete_map=None,
     line_dash_sequence=None,
     line_dash_map=None,
+    symbol_sequence=None,
+    symbol_map=None,
+    markers=False,
     direction="clockwise",
     start_angle=90,
     line_close=False,
@@ -1069,6 +1097,7 @@ def line_geo(
     hover_data=None,
     custom_data=None,
     line_group=None,
+    symbol=None,
     animation_frame=None,
     animation_group=None,
     category_orders=None,
@@ -1077,6 +1106,9 @@ def line_geo(
     color_discrete_map=None,
     line_dash_sequence=None,
     line_dash_map=None,
+    symbol_sequence=None,
+    symbol_map=None,
+    markers=False,
     projection=None,
     scope=None,
     center=None,

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

@@ -1773,8 +1773,13 @@ def infer_config(args, constructor, trace_patch, layout_patch):
             trace_patch["opacity"] = args["opacity"]
         else:
             trace_patch["marker"] = dict(opacity=args["opacity"])
-    if "line_group" in args:
-        trace_patch["mode"] = "lines" + ("+markers+text" if args["text"] else "")
+    if "line_group" in args:  # px.line, px.line_*, px.area
+        modes = set(["lines"])
+        if args.get("text") or args.get("symbol") or args.get("markers"):
+            modes.add("markers")
+        if args.get("text"):
+            modes.add("text")
+        trace_patch["mode"] = "+".join(modes)
     elif constructor != go.Splom and (
         "symbol" in args or constructor == go.Scattermapbox
     ):

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

@@ -325,6 +325,10 @@
         "Setting this value is recommended when using `plotly.express.colors.diverging` color scales as the inputs to `color_continuous_scale`.",
     ],
     size_max=["int (default `20`)", "Set the maximum mark size when using `size`."],
+    markers=[
+        "boolean (default `False`)",
+        "If `True`, markers are shown on lines.",
+    ],
     log_x=[
         "boolean (default `False`)",
         "If `True`, the x-axis is log-scaled in cartesian coordinates.",