List of lists in R

Question

I want to pre allocate a list containing lists of different length. The list will contain N rows and every row should contain another list with a specified length from another vector. It will look like this :

[[668]]
[1] 5096075

[[669]]
[1] 904607131

[[670]]
[1]  475127.3  430573.5 9046074.9

[[671]]
[1] 475121231237.3

[[672]]
[1] 0

[[673]]
[1] 43051273.5

[[674]]
[1] 41231230573.5

[[675]]
[1] 97304.1 

With the length of the list in the list is there any way to preallocate the space? The way its done now is to expand the list every time i loop it which takes alot of time

Answer 1

If lengths is your vector of lengths for each of the sub-lists then you can do:

lengths <- 1:10
lapply(lengths, vector, mode="list")