Populate list with same object efficiently

Question

Suppose I have some object (any object), for example:

X <- array(NA,dim=c(2,2))

Also I have some list:

L <- list()

I want L[[1]], L[[2]], L[[3]],...,L[[100]],...,L[[1000]] all to have the object X inside it. That is, if I type into the console L[[i]], it will return X, where i is in {1,2,...,1000}.

How do I do this efficiently without relying on a for loop or lapply?

Answer 1

Make a list of 1 and replicate it.

L <- rep(list(x), 1000)

Answer 2

Using replicate even if it still a kind of a loop solution:

L <- replicate(1000,X,simplify=FALSE)

EDIT benchmarkking the 2 solutions :

X <- array(NA,dim=c(2,2))
library(microbenchmark)
microbenchmark( rep(list(X), 10000),
               replicate(10000,X,simplify=FALSE))

                              expr      min       lq    median        uq      max neval
                  rep(list(X), 10000) 1.743070 2.114173  3.088678  5.178768 25.62722   100
replicate(10000, X, simplify = FALSE) 5.977105 7.573593 10.557783 13.647407 80.69774   100

rep is 5 times faster. I guess since replicate will evaluate the expression at each iteration.