addnode

Add new node to graph

Syntax

H = addnode(G,nodeIDs)

H = addnode(G,numNodes)

H = addnode(G,NodeProps)

Description

H = addnode(G,nodeIDs) adds the nodes specified by nodeIDs to graph G. The node names in nodeIDs must not refer to nodes already present in G.

H = addnode(G,numNodes) adds a number of new nodes to G equal to numNodes. If G contains nodes with names, then the new nodes are assigned sequential names indicating their row placement in G.Nodes.Name. For example, 'Node5' is located at G.Nodes.Name(5).

H = addnode(G,NodeProps) adds new nodes to G with the node properties in NodeProps. One node is added for each row in NodeProps. The NodeProps table must be able to be concatenated to G.Nodes, so that the result is H.Nodes = [G.Nodes; NodeProps].

Examples

Add Nodes to Graph

Add two nodes to a graph that does not have node names.

G = graph([1 2 3],[2 3 4])

G = 
  graph with properties:

    Edges: [3x1 table]
    Nodes: [4x0 table]

G = addnode(G,2)

G = 
  graph with properties:

    Edges: [3x1 table]
    Nodes: [6x0 table]

Add node names to the graph, and then add five additional new nodes. The auto-generated names for the new nodes indicate their placement in G.Nodes.Name.

G.Nodes.Name = {'A' 'B' 'C' 'D' 'E' 'F'}'

G = 
  graph with properties:

    Edges: [3x1 table]
    Nodes: [6x1 table]

G = addnode(G,5);
G.Nodes

ans=11×1 table
       Name   
    __________

    {'A'     }
    {'B'     }
    {'C'     }
    {'D'     }
    {'E'     }
    {'F'     }
    {'Node7' }
    {'Node8' }
    {'Node9' }
    {'Node10'}
    {'Node11'}

Add Named Nodes to Graph

Create a directed graph with named nodes, and then add two named nodes to the graph.

G = digraph({'A' 'B' 'C'},{'D' 'C' 'D'})

G = 
  digraph with properties:

    Edges: [3x1 table]
    Nodes: [4x1 table]

G = addnode(G,{'E' 'F'})

G = 
  digraph with properties:

    Edges: [3x1 table]
    Nodes: [6x1 table]

If the graph does not already have node names, then adding named nodes to the graph automatically generates names for the other nodes.

Create a directed graph without node names, and then add two named nodes to the graph.

H = digraph([1 2 3],[4 3 4])

H = 
  digraph with properties:

    Edges: [3x1 table]
    Nodes: [4x0 table]

H = addnode(H,{'E','F'});
H.Nodes

ans=6×1 table
      Name   
    _________

    {'Node1'}
    {'Node2'}
    {'Node3'}
    {'Node4'}
    {'E'    }
    {'F'    }

Add Nodes with Attributes to Graph

Create a graph whose nodes represent airports.

G = graph({'JFK' 'LAX'}, {'LAX' 'DEN'})

G = 
  graph with properties:

    Edges: [2x1 table]
    Nodes: [3x1 table]

Add a node attribute to indicate whether each airport has free Wi-Fi®.

G.Nodes.WIFI = [false true true]';
G.Nodes

ans=3×2 table
     Name      WIFI 
    _______    _____

    {'JFK'}    false
    {'LAX'}    true 
    {'DEN'}    true 

Add two new nodes to the graph by creating a table, NodeProps, containing the node name and Wi-Fi status of each new node. Use addnode to concatenate NodeProps to G.Nodes.

NodeProps = table({'ATL' 'ANC'}', [false true]', ...
    'VariableNames', {'Name' 'WIFI'});
G = addnode(G, NodeProps);

View the modified node table.

G.Nodes

ans=5×2 table
     Name      WIFI 
    _______    _____

    {'JFK'}    false
    {'LAX'}    true 
    {'DEN'}    true 
    {'ATL'}    false
    {'ANC'}    true 

Input Arguments

G — Input graph

graph object | digraph object

Input graph, specified as either a graph or digraph object. Use graph to create an undirected graph or digraph to create a directed graph.

Example: G = graph(1,2)

Example: G = digraph([1 2],[2 3])

nodeIDs — Node names

one or more node names

Node names, specified as one or more node names in one of these forms:

• Single Node — Character vector 'A' or string scalar "A".

• Multiple Nodes — Cell array of character vectors {'A' 'B' 'C'} or string array ["A" "B" "C"].

Example: H = addnode(G,'A')

Example: H = addnode(G,["A" "B" "C"])

Data Types: char | cell | string

numNodes — Number of nodes to add

nonnegative numeric scalar

Number of nodes to add, specified as a nonnegative numeric scalar.

NodeProps — Node attributes

table

Node attributes, specified as a table. NodeProps can contain any number of variables to describe attributes of the graph nodes, but must be able to be concatenated to G.Nodes, so that the result is H.Nodes = [G.Nodes; NodeProps]. For node names, use the variable Name, since this variable name is used by some graph functions. If there is a variable Name, then it must be a cell array of character vectors or string array specifying a unique name in each row. See table for more information on constructing a table.

Data Types: table

Output Arguments

H — Output graph

graph object | digraph object

Output graph, returned as a graph or digraph object.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The input argument nodeIDs that specifies node names is not supported.

• You cannot add new variables, or new columns, to the G.Nodes table after the graph object is created.

• When you construct a graph or digraph object in MATLAB^® and pass it to a MEX function generated using MATLAB Coder™, you cannot add nodes to the graph object.

• The node properties must be data types that can be stored as variable-size arrays in code generation. For example, the data type cannot be any of these:

  • a string array

  • a cell array with different sizes on each cell

  • a cell array of character vectors converted using cellstr

  • a user-defined class

Thread-Based Environment
Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

Version History

Introduced in R2015b