Allowing hover_data and custom_data to pass string of column name instead of list

Author: lukefeilberg

Diff for: packages/python/plotly/plotly/express/_core.py

@@ -1295,11 +1295,17 @@ def build_dataframe(args, constructor):
     # make copies of all the fields via dict() and list()
     for field in args:
         if field in array_attrables and args[field] is not None:
-            args[field] = (
-                dict(args[field])
-                if isinstance(args[field], dict)
-                else list(args[field])
-            )
+            if isinstance(args[field], dict):
+                args[field] = dict(args[field])
+            elif (
+                field in ["custom_data", "hover_data"]
+                and isinstance(args[field], str)
+                and "data_frame" in args.keys()
+                and args[field] in args["data_frame"].columns
+            ):
+                args[field] = [args[field]]
+            else:
+                list(args[field])
 
     # Cast data_frame argument to DataFrame (it could be a numpy array, dict etc.)
     df_provided = args["data_frame"] is not None

Diff for: packages/python/plotly/plotly/express/_doc.py

@@ -199,8 +199,8 @@
         "Values from this column or array_like appear in bold in the hover tooltip.",
     ],
     hover_data=[
-        "list of str or int, or Series or array-like, or dict",
-        "Either a list of names of columns in `data_frame`, or pandas Series,",
+        "str, or list of str or int, or Series or array-like, or dict",
+        "Either a name or list of names of columns in `data_frame`, or pandas Series,",
         "or array_like objects",
         "or a dict with column names as keys, with values True (for default formatting)",
         "False (in order to remove this column from hover information),",
@@ -211,8 +211,8 @@
         "Values from these columns appear as extra data in the hover tooltip.",
     ],
     custom_data=[
-        colref_list_type,
-        colref_list_desc,
+        "str, or list of str or int, or Series or array-like",
+        "Either name or list of names of columns in `data_frame`, or pandas Series, or array_like objects",
         "Values from these columns are extra data, to be used in widgets or Dash callbacks for example. This data is not user-visible but is included in events emitted by the figure (lasso selection etc.)",
     ],
     text=[