Allow edge tuple to be passed to get_edge().

Fixes #90.

--HG--
extra : convert_revision : svn%3A3ed01bd8-26fb-0310-9e4c-ca1a4053419f/networkx/trunk%40521

1 files changed, 6 insertions, 3 deletions

diff --git a/networkx/graph.py b/networkx/graph.py
index d62c8863..c6a77301 100644
--- a/networkx/graph.py
+++ b/networkx/graph.py
@@ -418,16 +418,19 @@ class Graph(object):
         return self.adj.has_key(u) and self.adj[u].has_key(v)
 
 
-    def get_edge(self, n1, n2):
+    def get_edge(self, u, v):
         """Return 1 if graph contains the edge u-v. 
         Raise an exception otherwise.
     
         """
         # useful for helping build adjacency matrix representation
-        if self.has_edge(n1,n2):
+        if v is None:
+            (u,v)=u
+
+        if self.has_edge(u,v):
             return 1
         else:
-            raise NetworkXError, "no edge (%s,%s) in graph"%(n1,n2)
+            raise NetworkXError, "no edge (%s,%s) in graph"%(u,v)
 
 
     def neighbors_iter(self,n):