由变量分组后的r相交元素

Question

我有一个数据看起来如下:

toy.dat <- data.frame(group = c(rep("A_0", 3), rep("A_1", 2), 
rep("B_0", 3) , rep("B_1", 3)))
toy.dat$letters <- c("A", 'B', "C", "A", "D", "C", "E", "F", "A", "B", "F")
toy.dat %>% 
group_by(group) %>% 
summarise(letters = list(letters), num = n()) %>%
mutate(group_number = gsub(".*_", "", group))

group   letters            num_elements  group_num   
A_0     c("A", "B", "C")       3              0        
A_1     c("A", "D")            2              1
B_0     c("C", "E", "F")       3              0
B_1     c("A", "B", "F")       3              1

我想按group_numb分组，找到这些行的字母的交集，并将它们添加到数据帧中。

输出应该给出"c"对于A_0和B_0和"A"对于A_1和B_1

Answer 1

我们可以用reduce

library(dplyr)
library(purrr)
toy.dat %>% group_by(group) %>% summarise(letters = list(letters), num = n()) %>%
mutate(group_number = gsub(".*_", "", group)) %>% group_by(group_number) %>% mutate(intersect = list(reduce(letters, intersect))) %>%
ungroup %>%
mutate(nintersect = lengths(intersect))

与产出

# A tibble: 4 × 6
group letters     num group_number intersect nintersect
<chr> <list>    <int> <chr>        <list>         <int>
1 A_0   <chr [3]>     3 0            <chr [1]>          1
2 A_1   <chr [2]>     2 1            <chr [1]>          1
3 B_0   <chr [3]>     3 0            <chr [1]>          1
4 B_1   <chr [3]>     3 1            <chr [1]>          1