How to filter in lapply list with conditionals lapply, Filter, Between in R?-CodePudding

I have this:

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- I have a list "res.list"

2- Combines columns 1 to "n" without repetition.

3- Filter results by condition and delet element is NULL

Expected output: "result"

[[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"

the code does not return the result Expected output, if you have any idea to improve and make it more generic it will be enlightening.

Best regards

CodePudding user response：

We may need

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