fixing bug for non-int node labels when plotting

xgi/drawing/layout.py

@@ -147,7 +147,13 @@ def barycenter_spring_layout(H, return_phantom_graph=False):
         G.add_edge(i, j)
 
     # Adding phantom nodes and connections therein
-    phantom_node_id = max(H.nodes) + 1
+    # I will start from the first int node-label available
+    try:
+        phantom_node_id = max([n for n in H.nodes if isinstance(n, int)]) + 1
+    except ValueError:
+        # The list of node-labels has no integers, so I start from 0
+        phantom_node_id = 0
+
     # Looping over the hyperedges of different order (from triples up)
     for d in range(2, max_edge_order(H) + 1):
         # Hyperedges of order d (d=2: triplets, etc.)
@@ -219,7 +225,13 @@ def weighted_barycenter_spring_layout(H, return_phantom_graph=False):
         G.add_edge(i, j, weight=d)
 
     # Adding phantom nodes and connections therein
-    phantom_node_id = max(H.nodes) + 1
+    # I will start from the first int node-label available
+    try:
+        phantom_node_id = max([n for n in H.nodes if isinstance(n, int)]) + 1
+    except ValueError:
+        # The list of node-labels has no integers, so I start from 0
+        phantom_node_id = 0
+
     # Looping over the hyperedges of different order (from triples up)
     for d in range(2, max_edge_order(H) + 1):
         # Hyperedges of order d (d=2: triplets, etc.)