Adding elements to a list in R (in nested lists)

Question

I have a nested list l3 as:

l1<- as.list(c(1,2,3,4,5))
l1

l2<- as.list(c(6,7,8,9,10))
l2

l3<- list(l1,l2)
l3

l3 shows as:

> l3
[[1]]
[[1]][[1]]
[1] 1

[[1]][[2]]
[1] 2

[[1]][[3]]
[1] 3

[[1]][[4]]
[1] 4

[[1]][[5]]
[1] 5


[[2]]
[[2]][[1]]
[1] 6

[[2]][[2]]
[1] 7

[[2]][[3]]
[1] 8

[[2]][[4]]
[1] 9

[[2]][[5]]
[1] 10

I need to add a third list l4 to l3 such that l3 becomes:

[[1]][[1]]
    [1] 1

to

[[2]][[5]]
    [1] 10


[[3]][[1]]
    [1] 30

[[3]][[2]]
    [1] 32

[[3]][[3]]
    [1] 33

[[3]][[4]]
    [1] 34

[[3]][[5]]
    [1] 35

where l4 was:

l4<- as.list(c(31,32,33,34,35))

how do I accomplish it? I've tried (c), list, even explicitly put the arguments and got an out of bounds error. What can I use to get this done?

Answer 1

It works with append and list:

append(l3, list(l4))

The result:

> str(append(l3, list(l4)))
List of 3
 $ :List of 5
  ..$ : num 1
  ..$ : num 2
  ..$ : num 3
  ..$ : num 4
  ..$ : num 5
 $ :List of 5
  ..$ : num 6
  ..$ : num 7
  ..$ : num 8
  ..$ : num 9
  ..$ : num 10
 $ :List of 5
  ..$ : num 31
  ..$ : num 32
  ..$ : num 33
  ..$ : num 34
  ..$ : num 35

Answer 2

I don't know what you have tried with c, but it works

c(l3,list(l4))

PS: append is a wrapper of c to insert in a specific index, (see after argument )