graph_from_adj_list

0th

Percentile

Create graphs from adjacency lists

An adjacency list is a list of numeric vectors, containing the neighbor vertices for each vertex. This function creates an igraph graph object from such a list.

Keywords
graphs
Usage
graph_from_adj_list(adjlist, mode = c("out", "in", "all", "total"),
  duplicate = TRUE)
Arguments
adjlist
The adjacency list. It should be consistent, i.e. the maximum throughout all vectors in the list must be less than the number of vectors (=the number of vertices in the graph). Note that the list is expected to be 0-indexed.
mode
Character scalar, it specifies whether the graph to create is undirected (all or total) or directed; and in the latter case, whether it contains the outgoing (out) or the incoming (in) ne
duplicate
Logical scalar. For undirected graphs it gives whether edges are included in the list twice. E.g. if it is TRUE then for an undirected {A,B} edge graph_from_adj_list expects A included in the neighbors o
Details

Adjacency lists are handy if you intend to do many (small) modifications to a graph. In this case adjacency lists are more efficient than igraph graphs.

The idea is that you convert your graph to an adjacency list by as_adj_list, do your modifications to the graphs and finally create again an igraph graph by calling graph_from_adj_list.

Value

  • An igraph graph object.

See Also

as_edgelist

Aliases
  • graph.adjlist
  • graph_from_adj_list
Examples
## Directed
g <- make_ring(10, dir=TRUE)
al <- as_adj_list(g, mode="out")
g2 <- graph_from_adj_list(al)
graph.isomorphic(g, g2)

## Undirected
g <- make_ring(10)
al <- as_adj_list(g)
g2 <- graph_from_adj_list(al, mode="all")
graph.isomorphic(g, g2)
ecount(g2)
g3 <- graph_from_adj_list(al, mode="all", duplicate=FALSE)
ecount(g3)
which_multiple(g3)
Documentation reproduced from package igraph, version 1.0.0, License: GPL (>= 2)

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