生成igraph中每个顶点的边缘权重列表

Question

The igraph function:

nn.list <- adjacent_vertices(g, V(g))

outputs a list of adjacent vertices for each vertex.

This is very useful. But now I need a similar list containing the edge weights.

For example, if vertex 600 has the follow adjacent vertices 597, 598, 599, 601 found from nn.list[[600]] , I now need a list where entry 600 gives the edge weights between vertex 600 and each of the adjacent vertices 597, 598, 599, 601 .

I can do this with a for loop - but it's slow. My network has about 10^4 nodes and 10^5 edges. I'm looking for a vectorized approach. Is there a built in functions in igraph would help me do this? Any suggestions?

Answer 1

library(igraph)
g<-make_empty_graph(directed = F)

g<-add.vertices(g,c(10))

g<-add_edges(g,c(3,5))
g<-add_edges(g,c(4,5))
g<-set_edge_attr(graph = g,name="weight",index = E(g)[1],value = 0.3)
g<-set_edge_attr(graph = g,name="weight",index = E(g)[2],value = 10)


gedges<-E(g)
gweights <- E(g)$weight

as_adj(g)


 as_adj(g,attr="weight")

as_adj(g)
as_adj(g,attr="weight")
as_adj(g,attr="weight", edges = T,sparse = F)

If you want to retrieve a vector of ALL edges, use E(g) , if you want a vector of ALL weights use E(g)$weight

Then, as you seem to need an adjacency matrix you can use as_adj tweaking the params until you get all info you want to!