Upgrade to Py36 syntax

$ find examples -name \*.py -exec pyupgrade --py36-plus {} \;

6 files changed, 12 insertions, 13 deletions

diff --git a/examples/drawing/plot_chess_masters.py b/examples/drawing/plot_chess_masters.py
index ca2f3ef5..4bb877c1 100644
--- a/examples/drawing/plot_chess_masters.py
+++ b/examples/drawing/plot_chess_masters.py
@@ -79,7 +79,7 @@ if len(Gcc) > 1:
     print(Gcc[1].nodes())
 
 # find all games with B97 opening (as described in ECO)
-openings = set([game_info["ECO"] for (white, black, game_info) in G.edges(data=True)])
+openings = {game_info["ECO"] for (white, black, game_info) in G.edges(data=True)}
 print(f"\nFrom a total of {len(openings)} different openings,")
 print("the following games used the Sicilian opening")
 print('with the Najdorff 7...Qb6 "Poisoned Pawn" variation.\n')
diff --git a/examples/drawing/plot_knuth_miles.py b/examples/drawing/plot_knuth_miles.py
index e4b016c9..1a745f19 100644
--- a/examples/drawing/plot_knuth_miles.py
+++ b/examples/drawing/plot_knuth_miles.py
@@ -43,7 +43,7 @@ def miles_graph():
         if line.startswith("*"):  # skip comments
             continue
 
-        numfind = re.compile("^\d+")
+        numfind = re.compile(r"^\d+")
 
         if numfind.match(line):  # this line is distances
             dist = line.split()
diff --git a/examples/drawing/plot_lanl_routes.py b/examples/drawing/plot_lanl_routes.py
index 07b9e5d0..bb99456a 100644
--- a/examples/drawing/plot_lanl_routes.py
+++ b/examples/drawing/plot_lanl_routes.py
@@ -23,7 +23,7 @@ def lanl_graph():
     """
     try:
         fh = open("lanl_routes.edgelist", "r")
-    except IOError:
+    except OSError:
         print("lanl.edges not found")
         raise
 
diff --git a/examples/graph/plot_roget.py b/examples/graph/plot_roget.py
index 19ff547b..4f8df1a4 100644
--- a/examples/graph/plot_roget.py
+++ b/examples/graph/plot_roget.py
@@ -50,7 +50,7 @@ def roget_graph():
         (headname, tails) = line.split(":")
 
         # head
-        numfind = re.compile("^\d+")  # re to find the number of this word
+        numfind = re.compile(r"^\d+")  # re to find the number of this word
         head = numfind.findall(headname)[0]  # get the number
 
         G.add_node(head)
diff --git a/examples/graph/plot_words.py b/examples/graph/plot_words.py
index bfe3eb50..ccaaebb7 100644
--- a/examples/graph/plot_words.py
+++ b/examples/graph/plot_words.py
@@ -24,7 +24,7 @@ import networkx as nx
 
 def generate_graph(words):
     G = nx.Graph(name="words")
-    lookup = dict((c, lowercase.index(c)) for c in lowercase)
+    lookup = {c: lowercase.index(c) for c in lowercase}
 
     def edit_distance_one(word):
         for i in range(len(word)):
diff --git a/examples/subclass/plot_antigraph.py b/examples/subclass/plot_antigraph.py
index d49943c1..3543da36 100644
--- a/examples/subclass/plot_antigraph.py
+++ b/examples/subclass/plot_antigraph.py
@@ -54,10 +54,9 @@ class AntiGraph(nx.Graph):
            The adjacency dictionary for nodes connected to n.
 
         """
-        return dict(
-            (node, self.all_edge_dict)
-            for node in set(self.adj) - set(self.adj[n]) - set([n])
-        )
+        return {
+            node: self.all_edge_dict for node in set(self.adj) - set(self.adj[n]) - {n}
+        }
 
     def neighbors(self, n):
         """Return an iterator over all neighbors of node n in the
@@ -65,7 +64,7 @@ class AntiGraph(nx.Graph):
 
         """
         try:
-            return iter(set(self.adj) - set(self.adj[n]) - set([n]))
+            return iter(set(self.adj) - set(self.adj[n]) - {n})
         except KeyError:
             raise NetworkXError(f"The node {n} is not in the graph.")
 
@@ -109,7 +108,7 @@ class AntiGraph(nx.Graph):
                     n,
                     {
                         v: self.all_edge_dict
-                        for v in set(self.adj) - set(self.adj[n]) - set([n])
+                        for v in set(self.adj) - set(self.adj[n]) - {n}
                     },
                 )
                 for n in self.nodes()
@@ -123,7 +122,7 @@ class AntiGraph(nx.Graph):
                     n,
                     {
                         v: self.all_edge_dict
-                        for v in set(self.nodes()) - set(self.adj[n]) - set([n])
+                        for v in set(self.nodes()) - set(self.adj[n]) - {n}
                     },
                 )
                 for n in self.nbunch_iter(nbunch)
@@ -153,7 +152,7 @@ class AntiGraph(nx.Graph):
 
         """
         for n in self.adj:
-            yield (n, set(self.adj) - set(self.adj[n]) - set([n]))
+            yield (n, set(self.adj) - set(self.adj[n]) - {n})
 
 
 # Build several pairs of graphs, a regular graph