# [R] Vectors of objects...

Randall Skelton rhskelto at atm.ox.ac.uk
Mon Nov 19 17:42:49 CET 2001

```Surely I am confused about something... still.  Having read parts of
S-programming, MASS, and Programming with Data, I am no closer to
understanding how to make a simple vector containing list objects. If I
have somehow skipped over a relevant section in these books, please let me
know what sections I should have read.  This is a simpler case of what I
posted on Friday.  I am trying to build something in R that resembles an
array of structures in C.

> # Create some simple objects (ordinarily objects generated by a function)
> object <- list(a="test", b=c(1.0,2.0,3.0,4.0))
> object2 <- list(a="test2", b=c(2.0,4.0,6.0,8.0))
> # Create a vector of length 2
> mega <- 1:2

At this point I want to insert object 1 into the first element of the
vector 'mega' and object 2 into the second element.

> mega[[1]] <- object
Error: more elements supplied than there are to replace
> print(mega)
[1] 1 2

No luck there...

> mega[1] <- object
Warning message:
number of items to replace is not a multiple of replacement length
> print(mega)
[[1]]
[1] "test"

[[2]]
[1] 2

Still no luck... BUT, if I once again try:

> mega[[1]] <- object
> print(mega)
[[1]]
[[1]]\$a
[1] "test"

[[1]]\$b
[1] 1 2 3 4

[[2]]
[1] 2

Moreover,

> mega[[2]] <- object2
> print(mega)
[[1]]
[[1]]\$a
[1] "test"

[[1]]\$b
[1] 1 2 3 4

[[2]]
[[2]]\$a
[1] "test2"

[[2]]\$b
[1] 2 4 6 8

Clearly I am missing something here.  The end result of 'mega' is exactly
what I wanted in the first place, but it seems I needed to make 2 mistakes
before I could get there?  Can someone please explain?

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```