Hi, is there a way to get the key 'id' of edges in the spirit of the vertices one like the following? _vertexIds works but not _edgeIds. g=load_graph(dataFolder+'networkFullyConnected.xml') _vertexIds = g.vertex_properties["_graphml_vertex_id"] _edgeIds = g.edge_properties["_graphml_edge_id"] The result is Traceback (most recent call last): File "edgesProperties.py", line 18, in <module> _edgeIds = g.edge_properties["_graphml_edge_id"] File "/usr/lib/python2.7/site-packages/graph_tool/__init__.py", line 995, in __getitem__ val = self.get_func(self.g, key) File "/usr/lib/python2.7/site-packages/graph_tool/__init__.py", line 1469, in <lambda> lambda g, k: g.__properties[("e", k)], KeyError: ('e', '_graphml_edge_id') And the network in graphml framework reads as <edge id="1" source="65091" target="65221"> <data key="w">192.49624317</data> </edge> <node id="16071"> <data key="o">5.41539461304e-05</data> <data key="d">2.03027821579e-05</data> </node> Thanks, F.