Extract a subgraph that contains node 'B' and all of its neighbors. subgraph preserves the node names and edge weights. However, the numeric node IDs in H are renumbered compared to G.

N = neighbors(G,'B');
H = subgraph(G, ['B'; N]);
plot(H,'EdgeLabel',H.Edges.Weight)

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 identifiers node indices | node names

Node identifiers, specified as one or more node indices or node names.
nodeIDs selects a subset of the nodes in
G to generate the subgraph,
H.

This table shows the different ways to refer to one or more nodes either by their numeric node indices or by their node names.

Form

Single Node

Multiple Nodes

Node index

Scalar

Example:1

Vector

Example:[1 2 3]

Node name

Character vector

Example:'A'

Cell array of character vectors

Example:{'A' 'B' 'C'}

String scalar

Example:"A"

String array

Example:["A" "B" "C"]

Example: H = subgraph(G,[1 2 5])

Example: H = subgraph(G,{'A' 'B' 'E'})

idx — Node selection vector vector

Node selection vector, specified as a logical vector. The subgraph
contains only the nodes J for which
idx(J) is logical 1
(true). The index of node J in
H is I(J), where I =
find(idx).

Subgraph, returned as a graph or
digraph object. H contains only
the nodes that were selected with nodeIDs or
idx. Other nodes in G (and the
edges connecting to those nodes) are discarded. The node properties and edge
properties of the selected nodes and edges are carried over from
G into H.

See graph or digraph for more information
about graph objects.

Extended Capabilities

C/C++ Code Generation Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

The node identifiers nodeIDs must be node indices
of the input graph G. Node names are not
supported.

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