An addition to the accepted answer: if you want to add a vector to other elements in a longer list, as.list() may not produce what you expect. For example: you want to add 2 text elements and a vector of five numeric elements (1:5), to make a list that is 7 elements long.
L<-list("a","b",as.list(1:5))
Oops: it returns a list with 3 elements, and the third element has a sub-list of 5 elements; not what we wanted! The solution is to join two separate lists:
L1<-list("a","b")
L2<-as.list(1:5)
L<-c(L1,L2) #7 elements, as expected