R is very particular about what can be contained in a vector. All the elements need to be of the same type, an moreover must be either types of number^[1], logical values, or strings of text^[2].If you want a collection of elements which are of different types, or not of one of the allowed vector types, you need to use alist.

l1 <- list(a=1, b=1:3)l2 <- c(sqrt, log) #