px.IdentityMap

Author: nicolaskruchten

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

@@ -53,6 +53,7 @@
     set_mapbox_access_token,
     defaults,
     get_trendline_results,
+    IdentityMap,
 )
 
 from . import data, colors  # noqa: F401
@@ -95,4 +96,5 @@
     "colors",
     "set_mapbox_access_token",
     "get_trendline_results",
+    "IdentityMap",
 ]

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

@@ -41,6 +41,24 @@ def __init__(self):
 defaults = PxDefaults()
 del PxDefaults
 
+
+class IdentityMap(object):
+    """
+    `dict`-like object which can be passed in to arguments like `color_discrete_map` to
+    use the provided data values as colors, rather than mapping them to colors cycled
+    from `color_discrete_sequence`.
+    """
+
+    def __getitem__(self, key):
+        return key
+
+    def __contains__(self, key):
+        return True
+
+    def copy(self):
+        return self
+
+
 MAPBOX_TOKEN = None
 
 
@@ -1404,9 +1422,10 @@ def make_figure(args, constructor, trace_patch={}, layout_patch={}):
         for col, val, m in zip(grouper, group_name, grouped_mappings):
             if col != one_group:
                 key = get_label(args, col)
-                mapping_labels[key] = str(val)
-                if m.show_in_trace_name:
-                    trace_name_labels[key] = str(val)
+                if not isinstance(m.val_map, IdentityMap):
+                    mapping_labels[key] = str(val)
+                    if m.show_in_trace_name:
+                        trace_name_labels[key] = str(val)
                 if m.variable == "animation_frame":
                     frame_name = val
         trace_name = ", ".join(trace_name_labels.values())

Diff for: packages/python/plotly/plotly/tests/test_core/test_px/test_px_input.py

@@ -323,3 +323,18 @@ def test_size_column():
     df = px.data.tips()
     fig = px.scatter(df, x=df["size"], y=df.tip)
     assert fig.data[0].hovertemplate == "size=%{x}<br>tip=%{y}<extra></extra>"
+
+
+def test_identity_map():
+    fig = px.scatter(
+        x=[1, 2],
+        y=[1, 2],
+        symbol=["a", "b"],
+        color=["red", "blue"],
+        color_discrete_map=px.IdentityMap(),
+    )
+    assert fig.data[0].marker.color == "red"
+    assert fig.data[1].marker.color == "blue"
+    assert "color" not in fig.data[0].hovertemplate
+    assert "symbol" in fig.data[0].hovertemplate
+    assert fig.layout.legend.title.text == "symbol"