Minor bug fix for adding custom node attributes (#2723)

holoviews/element/graphs.py

@@ -400,7 +400,7 @@ def from_networkx(cls, G, layout_function, nodes=None, **kwargs):
             idx_dim = nodes.kdims[-1].name
             xs, ys = zip(*[v for k, v in sorted(positions.items())])
             indices = list(nodes.dimension_values(idx_dim))
-            edges = [(src, tgt) for (src, tgt) in edges if src in indices and tgt in indices]
+            edges = [edge for edge in edges if edge[0] in indices and edge[1] in indices]
             nodes = nodes.select(**{idx_dim: [eid for e in edges for eid in e]}).sort()
             nodes = nodes.add_dimension('x', 0, xs)
             nodes = nodes.add_dimension('y', 1, ys).clone(new_type=cls.node_type)

tests/element/testgraphelement.py

@@ -167,6 +167,19 @@ def test_from_networkx_only_nodes(self):
         G.add_nodes_from([1, 2, 3])
         graph = Graph.from_networkx(G, nx.circular_layout)
         self.assertEqual(graph.nodes.dimension_values(2), np.array([1, 2, 3]))
+
+    @attr(optional=1)
+    def test_from_networkx_custom_nodes(self):
+        try:
+            import networkx as nx
+        except:
+            raise SkipTest('Test requires networkx to be installed')
+        FG = nx.Graph()
+        FG.add_weighted_edges_from([(1,2,0.125), (1,3,0.75), (2,4,1.2), (3,4,0.375)])
+        nodes = Dataset([(1, 'A'), (2, 'B'), (3, 'A'), (4, 'B')], 'index', 'some_attribute')
+        graph = Graph.from_networkx(FG, nx.circular_layout, nodes=nodes)
+        self.assertEqual(graph.nodes.dimension_values('some_attribute'), np.array(['A', 'B', 'A', 'B']))
+
 
 class ChordTests(ComparisonTestCase):