Create Graph

Create a directed graph. The corresponding elements insandtdefine the source and target nodes of each edge in the graph.

s = [1 1 2 2 3]; t = [2 4 3 4 4]; G = digraph(s,t)

G = digraph with properties: Edges: [5x1 table] Nodes: [4x0 table]

Add Node Names

Add node names to the graph by adding the variable,Name, to theG.Nodestable. TheNamevariable must be specified as anN-by-1cell array of character vectors or string array, whereN = numnodes(G). It is important to use theNamevariable when adding node names, as this variable name is treated specially by some graph functions.

G.Nodes.Name = {'First''Second''Third''Fourth'}';

View the newNodestable.

G.Nodes

ans=4×1 tableName __________ {'First' } {'Second'} {'Third' } {'Fourth'}

Use table indexing to view the names of nodes 1 and 4.

G.Nodes.Name([1 4])

ans =2x1 cell{'First' } {'Fourth'}

Add Edge Weights

Add edge weights to the graph by adding the variable,Weight, to theG.Edgestable. TheWeightvariable must be anM-by-1 numeric vector, whereM = numedges(G). It is important to use theWeightvariable when adding edge weights, as this variable name is treated specially by some graph functions.

G.Edges.Weight = [10 20 30 40 50]';

View the newEdgestable.

G.Edges

ans=5×2 tableEndNodes Weight ________________________ ______ {'First' } {'Second'} 10 {'First' } {'Fourth'} 20 {'Second'} {'Third' } 30 {'Second'} {'Fourth'} 40 {'Third' } {'Fourth'} 50

Use table indexing to view the first and third rows ofG.Edges.

G.Edges([1 3],:)

ans=2×2 tableEndNodes Weight ________________________ ______ {'First' } {'Second'} 10 {'Second'} {'Third' } 30

Add Custom Attributes

In principle you can add any variable toG.NodesandG.Edgesthat defines an attribute of the graph nodes or edges. Adding custom attributes can be useful, since functions likesubgraphandreordernodespreserve the graph attributes.

For example, add a variable namedPowertoG.Edgesto indicate whether each edge is'on'or'off'.

G.Edges.Power = {'on''on''on''off''off'}'; G.Edges

ans=5×3 tableEndNodes Weight Power ________________________ ______ _______ {'First' } {'Second'} 10 {'on' } {'First' } {'Fourth'} 20 {'on' } {'Second'} {'Third' } 30 {'on' } {'Second'} {'Fourth'} 40 {'off'} {'Third' } {'Fourth'} 50 {'off'}

Add a variable named大小toG.Nodesto indicate the physical size of each node.

G.Nodes.Size = [10 20 10 30]'; G.Nodes

ans=4×2 tableName Size __________ ____ {'First' } 10 {'Second'} 20 {'Third' } 10 {'Fourth'} 30

Modify Tables with Variables Editor

SinceNodesandEdgesare both tables, you can use the Variables editor to interactively view or edit the tables. For more information, seeCreate and Edit Variables.

Label Nodes and Edges of Graph Plot

When you plot a graph, you can use the variables inG.NodesandG.Edgesto label the graph nodes and edges. This practice is convenient, since these variables are already guaranteed to have the correct number of elements.

Plot the graph and label the edges using thePowervariable inG.Edges. Label the nodes using the大小variable inG.Nodes.

p = plot(G,'EdgeLabel',G.Edges.Power,'NodeLabel',G.Nodes.Size)

p = GraphPlot with properties: NodeColor: [0 0.4470 0.7410] MarkerSize: 4 Marker: 'o' EdgeColor: [0 0.4470 0.7410] LineWidth: 0.5000 LineStyle: '-' NodeLabel: {'10' '20' '10' '30'} EdgeLabel: {'on' 'on' 'on' 'off' 'off'} XData: [2 1.5000 1 2] YData: [4 3 2 1] ZData: [0 0 0 0] Show all properties