library(data.table)
dt <- data.table(num=runif(3), char = letters[1:3])
str(data.table::transpose(dt)) # I want a data.table, so fine.
# Classes ‘data.table’ and 'data.frame':	2 obs. of  3 variables:
#  $ V1: chr  "0.21412930265069" "a"
#  $ V2: chr  "0.0449177662376314" "b"
#  $ V3: chr  "0.299894759198651" "c"
#  - attr(*, ".internal.selfref")=<externalptr> 
str(data.table::transpose(as.list(dt))) # I want a list, so it should be a list of lists.
# List of 3
#  $ : chr [1:2] "0.21412930265069" "a"
#  $ : chr [1:2] "0.0449177662376314" "b"
#  $ : chr [1:2] "0.299894759198651" "c"
library(purrr)
str(purrr::transpose(dt)) # Exactly right!
# List of 3
#  $ :List of 2
#   ..$ num : num 0.214
#   ..$ char: chr "a"
#  $ :List of 2
#   ..$ num : num 0.0449
#   ..$ char: chr "b"
#  $ :List of 2
#   ..$ num : num 0.3
#   ..$ char: chr "c"