I have a list

```
> (mylist <- list(list(a=1),list(a=2),list(a=3)))
[[1]]
[[1]]$a
[1] 1
[[2]]
[[2]]$a
[1] 2
[[3]]
[[3]]$a
[1] 3
```

and I want to add field `b`

to each sublist from `11:13`

to get something like

```
> (mylist <- list(list(a=1,b=11),list(a=2,b=12),list(a=3,b=13)))
[[1]]
[[1]]$a
[1] 1
[[1]]$b
[1] 11
[[2]]
[[2]]$a
[1] 2
[[2]]$b
[1] 12
[[3]]
[[3]]$a
[1] 3
[[3]]$b
[1] 13
```

How do I do this?

(note that I have a large number of such relatively small lists, so this will be called in `apply`

and has to be reasonably fast).

`lapply(mylist, function(l) {l$b <- l$a+10; l})`

should work, so long as you're actually adding 10 to each`a`

value...