Question

I can make this list by hand:

list( list(n=1) , list(n=2), list(n=3) )

But how do I automate this, for instance if I want n to go up to 10? I tried as.list(1:10), which firstly is a different type of data structure, and secondly I couldn’t work out how to specify n.

I’m hoping the answer can be expanded to multiple element lists, e.g. all combinations of 1:3 and c(‘A’,’B’):

list( list(n=1,z='A') , list(n=2,z='A'), list(n=3,z='A'),
      list(n=1,z='B') , list(n=2,z='B'), list(n=3,z='B') )

Background: I’ll be using it along the lines of: lapply( outer_list, function(params) do.call(FUN,params) )

UPDATE:
It was difficult to choose which answer to give the tick to. I went with the expand.grid approach as it can scale to more than two parameters more easily; the use of mapply as shown in the comment makes the two examples above look reasonably compact and readable:

outer_list=with( expand.grid(n=1:10,stringsAsFactors=F),
    mapply(list, n=n, SIMPLIFY=F)
    )

outer_list=with( expand.grid(n=1:3,z=c('A','Z'), stringsAsFactors=F),
    mapply(list, n=n, z=z, SIMPLIFY=F)
    )

They violate the DRY principle, by repeating the parameter names in the mapply() call, which bothers me a little. So, when it bothers me enough I will use the alply call as shown in Sebastian’s answer.

Answer 1

vals <- expand.grid(n=1:3, z=c("A", "B"), 
                      KEEP.OUT.ATTRS=FALSE, stringsAsFactors=FALSE)

library(plyr)
alply(vals, 1, as.list)

$`1`
$`1`$n
[1] 1

$`1`$z
[1] "A"


$`2`
$`2`$n
[1] 2

$`2`$z
[1] "A"


$`3`
$`3`$n
[1] 3

$`3`$z
[1] "A"


$`4`
$`4`$n
[1] 1

$`4`$z
[1] "B"


$`5`
$`5`$n
[1] 2

$`5`$z
[1] "B"


$`6`
$`6`$n
[1] 3

$`6`$z
[1] "B"


attr(,"split_type")
[1] "array"
attr(,"split_labels")
  n z
1 1 A
2 2 A
3 3 A
4 1 B
5 2 B
6 3 B