Remove same element from vector

I have this vector

E=[1,2;1,3;1,6;2,3;2,4;3,7;4,5;5,6;5,7;6,7;1,2;2,4;6,8];

I want to omit same element and also (6,8).

As 8 is not conneted to other points, I want to omit it too.

result is: E=[1,2;1,3;1,6;2,3;2,4;3,7;4,5;5,6;5,7;6,7];

Answer 1

[Andrei Bobrov]

a = sort(unique(E,'rows'),2);
b = unique(a(:));
c = hist(a(:),b);
out = a(all(ismember(a,b(c > 1)),2),:);

Answer 2

[madhan ravi]

E=[1,2;1,3;1,6;2,3;2,4;3,7;4,5;5,6;5,7;6,7;1,2;2,4;6,8];
[E,~,~]=unique(E,'rows');
idx=ismember(E,[6 8],'rows');
E=E(~idx,:) %expected result

command window:

>> E
E =
     1     2
     1     3
     1     6
     2     3
     2     4
     3     7
     4     5
     5     6
     5     7
     6     7
>> 

[NA]

But I want a code that recognize [6 8] automatically. find that 8 is not connect to others.

Answer 3

[Guillaume]

What you have completely failed to mention in your question and left for us to guess is that your E matrix represents the edges of a graph. Without that information, "8 is not connected to other point" is meaningless.

One way to do what you want:

E=[1,2;1,3;1,6;2,3;2,4;3,7;4,5;5,6;5,7;6,7;1,2;2,4;6,8];
g = graph(E(:, 1), E(:, 2));  %remove duplicate edges and make graph
g = simplify(g);  %remove duplicate edges and self loops
g = rmnode(g, find(degree(g) <= 1));  %remove isolated nodes or nodes with only one edge

E = g.Edges.EndNodes