如何在应用列表中使用条件词过滤，过滤，在R之间？

Question

我有这个：

res.list<-list(c("X2", "X3", "X4"), c("X2", "X3", "X4"), c("X1", "X2", "X3"))

result<- lapply(res.list, function(x) {
      unlist(lapply(seq_along(x), function(y) combn(x, y, list)), recursive = FALSE)
    })
result<-lapply(result, Filter,f = function(x){
    ifelse(
    seq_along(result)==1, 
    between(length(x),1,3),
    between(length(x),2,2)
    ) %>%.[!is.na(.)]})

1-我有一个清单"res.list“

2-合并列1至"n“，不重复。

3-按条件筛选结果，delet元素为空。

预期产出：“成果”

[[1]]
[[1]][[1]][1] "X2"
[[1]][[2]][1] "X3"
[[1]][[3]][1] "X4"
[[1]][[4]][1] "X2" "X3"
[[1]][[5]][1] "X2" "X4"
[[1]][[6]][1] "X3" "X4"
[[1]][[7]][1] "X2" "X3" "X4"

[[2]]
[[2]][[4]][1] "X2" "X3"
[[2]][[5]][1] "X2" "X4"
[[2]][[6]][1] "X3" "X4"

[[3]]
[[3]][[4]][1] "X2" "X3"
[[3]][[5]][1] "X2" "X4"
[[3]][[6]][1] "X3" "X4"

代码不返回结果预期的输出，如果您有任何改进和使其更通用的想法，这将具有启发性。

诚挚的问候

Answer 1

我们可能需要

result[-1] <- lapply(result[-1], \(x) x[between(lengths(x), 1, 2)])