如何在igraph中提取子图

Question

I want to extract a subgraph around that node.

library(visNetwork)
library(igraph)
library(dplyr)

g<-data.frame(a=c(LETTERS[1:5], LETTERS[2:6]),b=c(LETTERS[2:6],  LETTERS[7:11])) %>% 
        as.matrix %>% graph.edgelist() 

visIgraph(g) %>% 
       visHierarchicalLayout(sortMethod = "directed", 
                             direction = "LR",levelSeparation = 300)

I would like to extract subgraph start from "D", like this

data.frame(a=c(LETTERS[1:5], LETTERS[2:6]), b=c(LETTERS[2:6], LETTERS[7:11])) %>% 
    as.matrix %>% .[c(4,5,8,9,10),1:2] %>% 
    graph.edgelist() %>% visIgraph() %>% 
    visHierarchicalLayout(sortMethod = "directed", 
                          direction = "LR", levelSeparation = 300)

Is there a way to get it? Thanks.

Answer 1

Have you tried the induced.subgraph() function?

new.vertices<- V(g)[-c(1,2,3,7,8)]
g.sub <- induced.subgraph(graph = g, new.vertices)
visIgraph(g.sub) %>% 
  visHierarchicalLayout(sortMethod = "directed", 
                        direction = "LR",levelSeparation = 300)