R-igraph：将.csv文件转换为图形文件

Question

I have a .csv file with this structure:

a,b,c,d

a,c

c,b,a

where each line corresponds to a complete undirected graph.

That means: for the line 1, I would need an igraph result like:

a-b

a-c

a-d

b-c

b-d

c-d

Would you know an easy way to convert my .csv file to a such graph in R?

Answer 1

Not clear if you want a single graph or a list of graphs (1 for each line).

Assuming the latter:

v <- readLines(textConnection("a,b,c,d
a,c
c,b,a"))

library(igraph)
f <- function(x) graph.data.frame(t(combn(strsplit(x,",")[[1]],2)),directed=FALSE)
g <-lapply(v,f)
par(mfrow=c(1,length(g)))
lapply(g,plot)

Assuming the former (not much point in this).

g.full <- do.call(graph.union,g)
par(mfrow=c(1,1))
plot(g.full)