as.edgelist: Convert a network object into a numeric edgelist matrix

Description

Constructs an edgelist in a sorted format with defined attributes.

Usage

# S3 method for network
as.edgelist(
  x,
  attrname = NULL,
  as.sna.edgelist = FALSE,
  output = c("matrix", "tibble"),
  ...
)
# S3 method for matrix
as.edgelist(
  x,
  n,
  directed = TRUE,
  bipartite = FALSE,
  loops = FALSE,
  vnames = seq_len(n),
  ...
)
# S3 method for tbl_df
as.edgelist(
  x,
  n,
  directed = TRUE,
  bipartite = FALSE,
  loops = FALSE,
  vnames = seq_len(n),
  ...
)
is.edgelist(x)

Value

A matrix in which the first two columns are integers giving the tail (source) and head (target) vertex ids of each edge. The matrix will be given the class edgelist.

The edgelist has additional attributes attached to it:

attr(,"n") the number of vertices in the original network
attr(,"vnames") the names of vertices in the original network
attr(,"directed") logical, was the original network directed
attr(,"bipartite") was the original network bipartite
attr(,"loops") does the original network contain self-loops

Note that if the attrname attribute is used the resulting edgelist matrix will have three columns. And if attrname refers to a character attribute, the resulting edgelist matrix will be character rather than numeric unless output="tibble".

Arguments

x: a network object with additional class added indicating how it should be dispatched.
attrname: optionally, the name of an edge attribute to use for edge values; may be a vector of names if output="tibble"
as.sna.edgelist: logical; should the edgelist be returned in edgelist form expected by the sna package? Ignored if output="tibble"
output: return type: a matrix or a tibble; see as.matrix.network for the difference.
...: additional arguments to other methods
n: integer number of vertices in network, value passed to the 'n' flag on edgelist returned
directed: logical; is network directed, value passed to the 'directed' flag on edgelist returned
bipartite: logical or integer; is network bipartite, value passed to the 'bipartite' flag on edgelist returned
loops: logical; are self-loops allowed in network?, value passed to the 'loops' flag on edgelist returned
vnames: vertex names (defaults to vertex ids) to be attached to edgelist for sna package compatibility

Details

Constructs a edgelist matrix or tibble from a network, sorted tails-major order, with tails first, and, for undirected networks, tail < head. This format is required by some reverse-depending packages (e.g. ergm)

The as.matrix.network.edgelist provides similar functionality but it does not enforce ordering or set the edgelist class and so should be slightly faster.

is.edgelist tests if an object has the class 'edgelist'

Examples

Run this code


   data(emon)
   as.edgelist(emon[[1]])
   as.edgelist(emon[[1]],output="tibble")
   # contrast with unsorted columns of
   as.matrix.network.edgelist(emon[[1]])