For string attributes use a categorical color scheme. (Instead of throwing an exception.)

lynxkite-app/web/src/workspace/Workspace.tsx

@@ -30,7 +30,6 @@ import NodeWithParams from './nodes/NodeWithParams';
 // import NodeWithTableView from './NodeWithTableView';
 import EnvironmentSelector from './EnvironmentSelector';
 import { LynxKiteState } from './LynxKiteState';
-import '@xyflow/react/dist/style.css';
 import { Workspace, WorkspaceNode } from "../apiTypes.ts";
 import NodeSearch, { OpsOp, Catalog, Catalogs } from "./NodeSearch.tsx";
 import NodeWithVisualization from "./nodes/NodeWithVisualization.tsx";

lynxkite-graph-analytics/src/lynxkite_plugins/graph_analytics/lynxkite_ops.py

@@ -249,13 +249,22 @@ def sample_graph(graph: nx.Graph, *, nodes: int = 100):
 
 
 def _map_color(value):
-    cmap = matplotlib.cm.get_cmap("viridis")
-    value = (value - value.min()) / (value.max() - value.min())
-    rgba = cmap(value)
-    return [
-        "#{:02x}{:02x}{:02x}".format(int(r * 255), int(g * 255), int(b * 255))
-        for r, g, b in rgba[:, :3]
-    ]
+    if pd.api.types.is_numeric_dtype(value):
+        cmap = matplotlib.cm.get_cmap("viridis")
+        value = (value - value.min()) / (value.max() - value.min())
+        rgba = cmap(value)
+        return [
+            "#{:02x}{:02x}{:02x}".format(int(r * 255), int(g * 255), int(b * 255))
+            for r, g, b in rgba[:, :3]
+        ]
+    else:
+        cmap = matplotlib.cm.get_cmap("Paired")
+        categories = pd.Index(value.unique())
+        colors = cmap.colors[: len(categories)]
+        return [
+            "#{:02x}{:02x}{:02x}".format(int(r * 255), int(g * 255), int(b * 255))
+            for r, g, b in [colors[categories.get_loc(v)] for v in value]
+        ]
 
 
 @op("Visualize graph", view="visualization")