在ggraph中有選擇地顏色/大小節點

Question

我正在使用tidygraph和ggraph繪制網絡。 有沒有辦法有選擇地操縱節點？ 具體來說，大小和顏色分開。

# example data
    rstat_nodes <- data.frame(name = c("Hadley", "David", "Romain", "Julia"))
    rstat_edges <- data.frame(from = c(1, 1, 1, 2, 3, 3, 4, 4, 4), 
                              to = c(2, 3, 4, 1, 1, 2, 1, 2, 3))
    gr <- tbl_graph(nodes = rstat_nodes, edges = rstat_edges)

    as_tbl_graph(gr) %>% 
      mutate(centrality = centrality_degree(normalized = T)) %>% 
      ggraph(layout = 'auto') + 
      #geom_edge_link() +
      geom_edge_arc(curvature=0.2,alpha=0.5) + 
      geom_node_point(aes(size = 0.2, colour = centrality)) + 
      scale_color_viridis(guide = 'legend') + 
      ggtitle("Network Degree Centrality (Normalized)") +
      theme_graph()

Answer 1

是的，你可以使用activate從tidygraph包訪問nodes和edges dataframes。 然后，您可以使用dplyr來操作每個文件中的數據。 你也可以直接管道到ggraph 。

library(tidyverse)
library(igraph)
library(ggraph)
library(tidygraph)
library(graphlayouts)
library(scales)


# example data
rstat_nodes <-
  data.frame(name = c("Hadley", "David", "Romain", "Julia"))
rstat_edges <- data.frame(from = c(1, 1, 1, 2, 3, 3, 4, 4, 4),
                          to = c(2, 3, 4, 1, 1, 2, 1, 2, 3))

gr <- tbl_graph(nodes = rstat_nodes, edges = rstat_edges)

gr %>% 
  activate(nodes) %>% # use dplyr on nodes
  mutate(David = 
           case_when(name == 'David' ~ 2, T ~ 0), 
         David = as.character(David)) %>% 
  activate(edges) %>% # same on edge list
  mutate(David = case_when(from == 2 ~ 1, T ~ 0), 
         David = as.character(David)) %>% 
  ggraph(., layout = 'auto')+
  geom_edge_link(aes(color = David), 
                 width = 1)+
  geom_node_point(aes(color = David), 
                  size = 5)+
  geom_node_text(aes(label = name), 
                 nudge_x = .05, 
                 nudge_y = .05)