Remove Isolated Nodes

Drops every node with no edges. Filtering edges deliberately keeps nodes (see filter_edges), so this is the explicit way to prune the isolates a filter left behind.

Usage

remove_isolates(x, keep_format = FALSE, directed = NULL)

Arguments

x

Network input: cograph_network, matrix, igraph, network, tna, or an edge-list data frame.

keep_format

Logical. If TRUE, matrix, igraph, statnet network and tna inputs are returned in that format. Default FALSE returns a cograph_network.

directed

Logical or NULL. If NULL (default), auto-detect.

Value

A cograph_network with the isolated nodes removed (or the input format when keep_format = TRUE). Node order is otherwise preserved and edge indices are remapped to the new node numbering.

See also

filter_edges, split_components, filter_nodes

Examples

adj <- matrix(0, 4, 4, dimnames = list(LETTERS[1:4], LETTERS[1:4]))
adj["A", "B"] <- adj["B", "A"] <- 1

# C and D have no edges
remove_isolates(adj)
#> Cograph network: 2 nodes, 1 edges ( undirected )
#> Source: matrix 
#>   Nodes (2): A, B
#>   Edges: 1 / 1 (density: 100.0%)
#>   Weights: [1.000, 1.000]  |  mean: 1.000
#>   Strongest edges:
#>     A -- B  1.000
#> Layout: none 
#>   Use as.data.frame() for the edge table, as.data.frame(what = "nodes") for the nodes.