igraph (version 1.0.0)

subgraph: Subgraph of a graph

Description

subgraph creates a subgraph of a graph, containing only the specified vertices and all the edges among them.

Usage

subgraph(graph, v)
induced_subgraph(graph, vids, impl = c("auto", "copy_and_delete",
  "create_from_scratch"))
subgraph.edges(graph, eids, delete.vertices = TRUE)

Arguments

graph

The original graph.

v

Numeric vector, the vertices of the original graph which will form the subgraph.

vids

Numeric vector, the vertices of the original graph which will form the subgraph.

impl

Character scalar, to choose between two implementation of the subgraph calculation. copy_and_delete copies the graph first, and then deletes the vertices and edges that are not included in the result graph. crea

eids

The edge ids of the edges that will be kept in the result graph.

delete.vertices

Logical scalar, whether to remove vertices that do not have any adjacent edges in eids.

Value

• A new graph object.

Details

induced_subgraph calculates the induced subgraph of a set of vertices in a graph. This means that exactly the specified vertices and all the edges between then will be kept in the result graph.

subgraph.edges calculates the subgraph of a graph. For this function one can specify the vertices and edges to keep. This function will be renamed to subgraph in the next major version of igraph.

The subgraph function does the same as induced.graph currently (assuming auto as the impl argument), but it is deprecated and will be removed in the next major version of igraph.

Examples

g <- make_ring(10)
g2 <- induced_subgraph(g, 1:7)
g3 <- subgraph.edges(g, 1:5, 1:5)