Transform an edgelist to a matrix

Usage

edgelist_to_matrix(
  E,
  digraph = TRUE,
  label = NULL,
  label2 = NULL,
  bipartite = FALSE,
  valued = FALSE,
  loops = FALSE,
  rule = c("weak", "strong")
)

Arguments

E: An edge list
digraph: Whether the matrix is directed or not
label: A vector with the names of the nodes, which gives their order in the matrix and adds the nodes without ties
label2: A vector with the names of the nodes of the second mode, with the same role as label, when bipartite = TRUE
bipartite: Whether the matrix is bipartite
valued: Whether the third column of the edgelist has the value of the tie
loops: Whether to keep the ties of a node with itself
rule: For digraph = FALSE, whether an undirected tie is kept when it is listed in either order (weak, default) or only when it is listed in both orders (strong), as in sna::symmetrize

Value

This function transform the edgelist into a matrix

Details

With digraph = FALSE each undirected tie is placed in both cells of the matrix, so the number of ties is the number of cells of one triangle (or half the sum of a binary matrix). A tie listed in both orders is a single tie.

The rows and the columns follow the order of label. The nodes that are not in label, or all the nodes when it is not given, are added in alphabetical order.

Author

Alejandro Espinosa-Rada

Examples

A <- matrix(c(
  0, 1, 1, 0, 0, 0, 0, 1, 0,
  1, 0, 1, 0, 0, 0, 0, 0, 0,
  1, 1, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 1, 1, 0, 0, 0,
  0, 0, 0, 1, 0, 0, 0, 0, 0,
  0, 0, 0, 1, 0, 0, 1, 1, 0,
  0, 0, 0, 0, 0, 1, 0, 1, 0,
  1, 0, 0, 0, 0, 1, 1, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0
), byrow = TRUE, ncol = 9)
rownames(A) <- letters[1:nrow(A)]
colnames(A) <- rownames(A)
E <- matrix_to_edgelist(A)
edgelist_to_matrix(E, label = c("i"), digraph = FALSE)
#>   i a b c d e f g h
#> i 0 0 0 0 0 0 0 0 0
#> a 0 0 1 1 0 0 0 0 1
#> b 0 1 0 1 0 0 0 0 0
#> c 0 1 1 0 0 0 0 0 0
#> d 0 0 0 0 0 1 1 0 0
#> e 0 0 0 0 1 0 0 0 0
#> f 0 0 0 0 1 0 0 1 1
#> g 0 0 0 0 0 0 1 0 1
#> h 0 1 0 0 0 0 1 1 0

# With a third column, the ties keep their value
V <- rbind(
  c("a", "b", 3),
  c("b", "c", 1),
  c("c", "a", 7)
)
edgelist_to_matrix(V, valued = TRUE)
#>   a b c
#> a 0 3 0
#> b 0 0 1
#> c 7 0 0