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% Generated by roxygen2 (4.1.1): do not edit by hand
% Please edit documentation in R/conversion.R
\name{graph_from_adj_list}
\alias{graph.adjlist}
\alias{graph_from_adj_list}
\title{Create graphs from adjacency lists}
\usage{
graph_from_adj_list(adjlist, mode = c("out", "in", "all", "total"),
duplicate = TRUE)
}
\arguments{
\item{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.}
\item{mode}{Character scalar, it specifies whether the graph to create is
undirected (\sQuote{all} or \sQuote{total}) or directed; and in the latter
case, whether it contains the outgoing (\sQuote{out}) or the incoming
(\sQuote{in}) neighbors of the vertices.}
\item{duplicate}{Logical scalar. For undirected graphs it gives whether
edges are included in the list twice. E.g. if it is \code{TRUE} then for an
undirected \code{{A,B}} edge \code{graph_from_adj_list} expects \code{A}
included in the neighbors of \code{B} and \code{B} to be included in the
neighbors of \code{A}.
This argument is ignored if \code{mode} is \code{out} or \code{in}.}
}
\value{
An igraph graph object.
}
\description{
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.
}
\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
\code{\link{as_adj_list}}, do your modifications to the graphs and finally
create again an igraph graph by calling \code{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)
}
\author{
Gabor Csardi \email{csardi.gabor@gmail.com}
}
\seealso{
\code{\link{as_edgelist}}
}
\keyword{graphs}
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