igraph (version 0.3.1)

conversion: Convert a graph to an adjacency matrix or an edge list

Description

Sometimes it is useful to have a standard representation of a graph, like an adjacency matrix or an edge list.

Usage

get.adjacency(graph, type="both", attr=NULL, names=TRUE, binary=FALSE)
get.edgelist(graph, names=TRUE)

Arguments

graph

The graph to convert.

type

Gives how to create the adjacency matrix for undirected graphs. It is ignored for directed graphs. Possible values: upper: the upper right triangle of the matrix is used, lower: the lower left triangle of the matrix i

attr

Either NULL or a character string giving an edge attribute name. If NULL a traditional adjacency matrix is returned. If not NULL then the values of the given edge attribute are included in the adjacency m

names

Logical constant.

For graph.adjacenct it gives whether to assign row and column names to the matrix. These are only assigned if the name vertex attribute is present in the graph.

for get.edgelist it

binary

Logical, whether to return a binary matrix. This argument is ignored if attr is not NULL.

Value

• A vcount(graph) by vcount(graph) (usually) numeric matrix for get.adjacency. (This can be huge!) Note that a non-numeric matrix might be returned if attr is a non-numeric edge attribute.

  A ecount(graph) by 2 numeric matrix for get.edgelist.

Details

get.adjacency returns the adjacency matrix of a graph.

get.edgelist returns the list of edges in a graph.

See Also

graph.adjacency, read.graph

Examples

g <- erdos.renyi.game(10, 2/10)
get.edgelist(g)
get.adjacency(g)
V(g)$name <- letters[1:vcount(g)]
get.adjacency(g)
E(g)$weight <- runif(ecount(g))
get.adjacency(g, attr="weight")