[R] Assignment Operator in mclapply

[Dario Strbenac]

I sometimes need to return multiple items from a loop. Is it possible to have the <<- operator work the same for mclapply as for lapply ?

> extra <- list()

> squares <- mclapply(1:10, function(x){extra[[x]] <<- x; x^2;})
> extra
list()

> squares <- lapply(1:10, function(x){extra[[x]] <<- x; x^2;})
> extra
[[1]]
[1] 1

[[2]]
[1] 2

[[3]]
[1] 3

[[4]]
[1] 4

[[5]]
[1] 5

[[6]]
[1] 6

[[7]]
[1] 7

[[8]]
[1] 8

[[9]]
[1] 9

[[10]]
[1] 10

My question is like that of http://tolstoy.newcastle.edu.au/R/e6/help/09/03/8329.html which is not answered.

--------------------------------------
Dario Strbenac
PhD Student
University of Sydney
Camperdown NSW 2050
Australia