List and order

[Peter Otten]

Nic wrote:

> The only problem is that from:
> 12
> 22
> 21
> In spite of writing
> 12 12 22
> it writes
> 12 21 22
> Do you know how is it possible to delete also this last trouble?

I thought that the two 12 were a typo, but it seems you want to reorder the
nodes inside an edge, too. Here's a fix that normalizes the edge before
sorting the list of edges:

edges = [sorted((ddeg[u], ddeg[v])) for u, v in G.edges()]
edges.sort()
for a, b in edges:
    print a, b,
print

Peter