如何在 R 中获取字符向量的所有可能子集？

Question

具有以下向量：

c("test1","test2","test3")

我正在尝试获取包含以下条目的列表或数据框：

"test1" "test2" "test3"
"test1" "test2" NA
"test1" NA "test3"
"test1"  NA NA
NA  "test2" "test3"
NA  "test2" NA
NA  NA "test3"

目标是获得所有可能的子集，而顺序无关紧要，即 "text1" "text2" NA 等同于 "text2" "text1" NA。我非常感谢任何帮助！

Answer 1

有相关功能的套餐。

library(sets)
a <- c("test1","test2","test3")
set_power(a)

{{}, {"test1"}, {"test2"}, {"test3"}, {"test1", "test2"}, {"test1", "test3"}, {"test2", "test3"}, {"test1", "test2", "test3"}}

这个returns所有子集的集合。

Answer 2

您可以使用 combn:

res <- unlist(lapply(1:3, combn, 
                     x = c("test1","test2","test3"), simplify = FALSE), 
              recursive = FALSE)
res <- sapply(res, `length<-`, 3)
#        [,1]    [,2]    [,3]    [,4]    [,5]    [,6]    [,7]   
#[1,] "test1" "test2" "test3" "test1" "test1" "test2" "test1"
#[2,] NA      NA      NA      "test2" "test3" "test3" "test2"
#[3,] NA      NA      NA      NA      NA      NA      "test3"

Answer 3

使用 combn 和 data.table::rbindlist with fill = TRUE 选项使 NA 值。

#data
a <- c("test1","test2","test3")

#result
data.table::rbindlist(
        sapply(1:3, function(i) as.data.frame(t(combn(a, i)))), fill = TRUE)

#output
#       V1    V2    V3
# 1: test1    NA    NA
# 2: test2    NA    NA
# 3: test3    NA    NA
# 4: test1 test2    NA
# 5: test1 test3    NA
# 6: test2 test3    NA
# 7: test1 test2 test3

如何在 R 中获取字符向量的所有可能子集？

How to get all possible subsets of a character vector in R?

r

subset