Combining each element of a list to elements of another list in R

Question

I have two list

list_1 <- list('A', 'B', 'C')

list_2 <- list('X', 'Y')

if I want the resultant list to be of the form

list_3 <- list('AX', 'AY', 'AZ', 'BX', 'BY', 'BZ', 'CX', 'CY', 'CZ')

The final list should be all possible combinations of the elements in both the lists without duplicates.

Answer 1

You can do the following:

as.list(outer(list_1,list_2, paste0))

Information regarding outer

Answer 2

You can do:

do.call(paste0, expand.grid(list_1, list_2))