rlistlapplyreshapemclapply

Reshape list created by lapply

I have vectors with latitudes and longitudes:

longDim
[1] -79.65770 -79.21761 -78.77750

latiDim
[1] -39.70588 -39.26471 -38.82353

and I wanted to loop over their combination in parallel. To do so, first I used expand.grid to create a data frame with all of their possible combinations:

my.grid <- expand.grid(longDim, latiDim)

and then I used mclapply() on the rows of the resulting data frame:

mclapply(1:nrow(my.grid), function(x){some_function})

where some_function returns a list with two objects, each with length 139.

Therefore, as a result I got a nested list with dimensions 9x2 that looks like this:

str(l1)
List of 9
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 2
  ..$ su.25: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ su.30: Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...

Now, I need to reshape this list from 9x2 to the 3x3x2 dimension again. This is the format I am looking for:

str(l2)
List of 3
 $ :List of 3
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 3
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
 $ :List of 3
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  ..$ :List of 2
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...
  .. ..$ : Named num [1:139] 0 0 0 0 0 0 0 0 0 0 ...
  .. .. ..- attr(*, "names")= chr [1:139] "1961" "1962" "1963" "1964" ...

How can I achieve that?

Code to reproduce l1 and l2 can be found at: https://pastebin.com/raw/LTyZi0mp (too long to post it here)

Solution

  • We can also use gl to create a grouping index for spliting

    split(lst, as.integer(gl(length(lst1), 3, length(lst1))))

    data

    lst1 <- replicate(9, list(list(x = 1:5, y = 1:5)))