Re: why I get error for these function?

[Andrew]

Just change

if (C in Subsets(G.neighbors(1))):

to

if (x!=y and C in Subsets(G.neighbors(1))):

It's probably more efficient to write something like:

N=Set(G.neighbors(1))
NN={x for x in G.neighbors(y) for y in N}  # neighbours of neighbours of 1
NN={x for x in NN if Set(G.neighbors(x)).issubset(N)}  # subset of NN with neighbours contained in N
print [(x,y) for (x,y) in CartesianProduct(NN,NN) if x!=y]

Andrew

On Thursday, 9 January 2014 08:27:25 UTC+1, Neda wrote:

 Hello, I want to compute this:

G= graphs.CompleteGraph(4)

G.delete_edge({1,2})

L = [u for u in G.vertices()]

for x in L:

    for y in L:

        A = Set(G.neighbors(x))

        B = Set(G.neighbors(y))

        C= A.union(B)

        if (C in Subsets(G.neighbors(1))):

            print(x,y)

the result is :

(1, 1)
(1, 2)
(2, 1)
(2, 2)

but I don't want the function prints (1,1) & (2,2)

so what should I write in the function to omit these pairs?