Question

This seems like an easy one (and it probably is), but since I’m braindead, I’m ready to get on the shame wall.

How to copy a list object n times, and wrap it up in a list afterwards? Something like this:

list(foo = "", bar = 0)

in order to get:

list(
    list(foo = "", bar = 0),
    list(foo = "", bar = 0)
    )

---

NOTE:
for loops are considered cheating

Answer 1

Well, rep works (and is “vectorized”) if you simply wrap the list in another list…

x <- list(foo = "", bar = 0)
rep(list(x), 2)

That trick can also be used to assign NULL to an element in a list:

x[2] <- list(NULL)