[Graph] Better string repr (#311)

python/dgl/graph.py

@@ -2907,3 +2907,9 @@ class DGLGraph(object):
         else:
             edges = F.tensor(edges)
             return edges[e_mask]
+
+    def __repr__(self):
+        s = 'DGLGraph with {node} nodes and {edge} edges.\nNode data: {ndata}\nEdge data: {edata}'
+        return s.format(node=self.number_of_nodes(), edge=self.number_of_edges(),
+                        ndata=str(self.node_attr_schemes()),
+                        edata=str(self.edge_attr_schemes()))

tests/mxnet/test_basics.py

@@ -439,6 +439,16 @@ def test_pull_0deg():
     check_pull_0deg(True)
     check_pull_0deg(False)
 
+def test_repr():
+    G = dgl.DGLGraph()
+    G.add_nodes(10)
+    G.add_edge(0, 1)
+    repr_string = G.__repr__()
+    G.ndata['x'] = mx.nd.zeros((10, 5))
+    G.add_edges([0, 1], 2)
+    G.edata['y'] = mx.nd.zeros((3, 4))
+    repr_string = G.__repr__()
+
 if __name__ == '__main__':
     test_batch_setter_getter()
     test_batch_setter_autograd()
@@ -451,3 +461,4 @@ if __name__ == '__main__':
     test_recv_0deg_newfld()
     test_update_all_0deg()
     test_pull_0deg()
+    test_repr()

tests/pytorch/test_basics.py

@@ -615,6 +615,17 @@ def test_dynamic_addition():
     assert g.edata['h1'].shape[0] == g.edata['h2'].shape[0] == 5
 
 
+def test_repr():
+    G = dgl.DGLGraph()
+    G.add_nodes(10)
+    G.add_edge(0, 1)
+    repr_string = G.__repr__()
+    G.ndata['x'] = th.zeros((10, 5))
+    G.add_edges([0, 1], 2)
+    G.edata['y'] = th.zeros((3, 4))
+    repr_string = G.__repr__()
+
+
 if __name__ == '__main__':
     test_nx_conversion()
     test_batch_setter_getter()
@@ -630,3 +641,4 @@ if __name__ == '__main__':
     test_pull_0deg()
     test_send_multigraph()
     test_dynamic_addition()
+    test_repr()