Exercise 4-7

# 1)
as.character(list(list(1, 2), list(3, list(4)), 5))

## [1] "list(1, 2)"       "list(3, list(4))" "5"

as.character(unlist(list(list(1, 2), list(3, list(4)), 5)))

## [1] "1" "2" "3" "4" "5"