在迭代列[R]中的唯一值时如何避免for循环

假设我们有以下玩具数据：

library(tidyverse)
data <- tibble(
  subject = c(1, 1, 1, 2, 2, 2, 2, 3, 3, 3),
  id1 = c("a", "a", "b", "a", "a", "a", "b", "a", "a", "b"),
  id2 = c("b", "c", "c", "b", "c", "d", "c", "b", "c", "c")
)

任务是计算每个网络的中心度。使用for循环这很简单：

library(igraph)
# Get unique subjects
subjects_uniq <- unique(data$subject)

# Compute centrality of nodes for each graph
for (i in 1:length(subjects_uniq)) {
  current_data <- data %>% filter(subject == i) %>% select(-subject)
  current_graph <- current_data %>% graph_from_data_frame(directed = FALSE)
  centrality <- eigen_centrality(current_graph)$vector
}

库（igraph）
#获得独特的主题
受试者\u uniq%选择（-subject）
当前\u图形%graph\u来自\u数据\u帧（directed=FALSE）
中心性这里有一个使用
map

library(tidyverse)
library(igraph)
map(subjects_uniq, ~data %>%
                    filter(subject == .x) %>%
                    select(-subject) %>%
                    graph_from_data_frame(directed = FALSE) %>% 
                    {eigen_centrality(.)$vector})
#[[1]]
#a b c 
#1 1 1 

#[[2]]
#        a         b         c         d 
#1.0000000 0.8546377 0.8546377 0.4608111 

#[[3]]
#a b c 
#1 1 1 

library(tidyverse)
library(igraph)
map(subjects_uniq, ~data %>%
                    filter(subject == .x) %>%
                    select(-subject) %>%
                    graph_from_data_frame(directed = FALSE) %>% 
                    {eigen_centrality(.)$vector})
#[[1]]
#a b c 
#1 1 1 

#[[2]]
#        a         b         c         d 
#1.0000000 0.8546377 0.8546377 0.4608111 

#[[3]]
#a b c 
#1 1 1