Remove duplicate edges of undirected graph

I am trying to remove duplicated edges of a garph.

I was able to get the unique edges by using

unique(G2.Edges.EndNodes)

However, this code only returns the unique edges without updating the G2.Edges table nor removing edges from the graph.

Any suggestion will be appreciated. Thanks.

My edges table look like this:

Answer 1

[Steven Lord]

Call simplify on your multigraph (you can tell if your graph or digraph is a multigraph using ismultigraph) to convert it to a simple graph.

s = [1 1 1 1 1 2 2 3 3 3 3 5 5];
t = [2 3 4 4 6 1 5 4 4 5 6 4 6];
names = string(1:6);
multiGraph = graph(s, t);
check = ismultigraph(multiGraph)

check = logical
   1

simpleGraph = simplify(multiGraph);

Let's compare how they look.

figure
h = plot(multiGraph);
title('multigraph');

figure
% Plot the simple graph with the vertices in the same location
% as the vertices in the multigraph
plot(simpleGraph, 'XData', h.XData, 'YData', h.YData)
title('simplegraph')

Answer 2

[Chunru]

% A graph with duplicated edges
s = [1 1 1 1 1 2 2 3 3 3 3 5 5];
t = [2 3 4 4 6 1 5 4 4 5 6 4 6];
names = string(1:6);
G = graph(s, t);

% A new graph with unique edges
G.Edges;
G1 = graph(unique(G.Edges));   % Create a new graph based on the unique edge rather than updating

subplot(121);
h1 = plot(G);
subplot(122)
h2 = plot(G1);

[IrisL]

Actually, I find that neither 'unique(G.Edges)' nor 'unique(G.Edges.EndNodes)' work.

If I use 'unique(G.Edges)', I got error message: Unable to group rows using unique values of the table variable 'EndNodes' because it is a cell array with more than one column.

If I use 'unique(G.Edges.EndNodes)' it only returns one column of unique node instead of unique edge(with two nodes).

Sorry if this situation changes my initial question.

[Chunru]

If you have node names specified, such as:

% A graph with duplicated edges
s = [1 1 1 1 1 2 2 3 3 3 3 5 5];
t = [2 3 4 4 6 1 5 4 4 5 6 4 6];
names = string(1:6);
G = graph(s, t, [], names);
% A new graph with unique edges
G.Edges   % EndNodes

ans = 13×1 table
       EndNodes   
    ______________

    {'1'}    {'2'}
    {'1'}    {'2'}
    {'1'}    {'3'}
    {'1'}    {'4'}
    {'1'}    {'4'}
    {'1'}    {'6'}
    {'2'}    {'5'}
    {'3'}    {'4'}
    {'3'}    {'4'}
    {'3'}    {'5'}
    {'3'}    {'6'}
    {'4'}    {'5'}
    {'5'}    {'6'}

% Using string array for unique (rather cell array)
newEdges = cellstr(unique(string(G.Edges.EndNodes), 'row'));
EdgeTable = table(newEdges, 'VariableNames', {'EndNodes'});
G1 = graph(EdgeTable);   % Create a new graph based on the unique edge rather than updating
subplot(121);
h1 = plot(G);
subplot(122)
h2 = plot(G1);

[IrisL]

Thanks. This is helpful as well!