如何从R中的另一个列表列表中删除列表列表？

Question

I have a two lists of lists generated by the following function:

 a <- replicate(10, sample(1:100,size=10), simplify=FALSE)
 b <- replicate(10, sample(1:100,size=10), simplify=FALSE)

Is there a way to remove numbers in 'b' lists from corresponding lists in 'a' so if:

a[1] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
b[1] = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11}

then the output would ideally be

c[1] = {1}

I was trying to do something like this but it didn't work:

for(i in 1:10){
index <- which( names(a[i]) %in% b[i])
a[i][-index]
}

Thanks ahead of time.

Answer 1

We can use Map with setdiff

Map(setdiff, b, a)

If it is the opposite

Map(setdiff, a, b)

Or another option is vsetdiff to preserve duplicate elements

library(vecsets)
Map(vsetdiff, a, b)

Or use %in% and negate ( ! )

Map(function(x, y) x[!x %in% y], a, b)

---

Or using for loop

for(i in seq_along(a)) a[[i]] <- a[[i]][!a[[i]] %in% b[[i]]]

Answer 2

additional solution

a <- list(c(1:10))
b <- list(c(2:11))

purrr::map2(.x = a, .y = b, .f = dplyr::setdiff)