将二部网络的 igraph 布局从垂直方向旋转到水平方向

Question

I have created a bipartite network with vertical orientation with:

edgelist <- read.table(text="Person    Event
                         Amy       football
                         Bob       picnic
                         Sam       artshow", 
                       header=TRUE)
igraph <- graph.data.frame(edgelist)

V(igraph)$type <- V(igraph)$name %in% edgelist[,1]
plot(igraph, vertex.label=V(igraph)$Name, vertex.size=7,vertex.label.dist=2, layout=layout_as_bipartite) 

I was wondering if I can create the same plot with horizontal orientation and the node names next to each node.

Answer 1

To get the original layout matrix, one can use the following code, after one have set the type of the graph:

LO <- layout_as_bipartite(igraph)

Now it has the correct coordinates for the bipartite plotting, but it plots the graph in two rows. To plot it in the desired orientation, one can flip the X and Y coordinates, by the backward indexing of the matrix.

plot(igraph, vertex.label=V(igraph)$Name, vertex.size=7,vertex.label.dist=2, layout=LO[,2:1])

Edit

I forgot that you want to reposition the labels. Fortunately, you have set the $type parameter as the indicator of the edges' tail nodes. You can use the vertex.label.degree argument of the plot function. Multiplying the mentioned logical vector attribute with pi has solved that problem too. So the position of the tails' labels are rotated by pi , while on the right, you have the labels rotated by 0. I have also plotted the labels a bit further from the nodes.

plot(igraph, vertex.label=V(igraph)$Name,
 vertex.size=7, vertex.label.dist=3, layout=LO[,2:1],
 vertex.label.degree = pi*V(igraph)$type)