Recursively Apply a Function to a List of Data Objects

rapply2d is a recursive version of lapply with two key differences to rapply: (1) Data frames are considered as final objects, not as (sub-)lists, and (2) the result is never simplified / unlisted.

rapply2d(l, FUN, ..., classes = "data.frame")

Arguments

l	a list.
FUN	a function that can be applied to all elements in l.
...	additional elements passed to FUN.
classes	character. These are classes of list-based objects inside l which FUN should be applied to. Note that FUN is also applied to all non-list elements in l. It is thus quite different from the classes argument to rapply.

Value

A list of the same structure as l, where FUN was applied to all final (atomic) elements and list-based objects of a class included in classes.

See also

rsplit, unlist2d, List Processing, Collapse Overview

Examples

l <- list(mtcars, list(mtcars, as.matrix(mtcars)))
rapply2d(l, fmean)
#> [[1]]
#>        mpg        cyl       disp         hp       drat         wt       qsec 
#>  20.090625   6.187500 230.721875 146.687500   3.596562   3.217250  17.848750 
#>         vs         am       gear       carb 
#>   0.437500   0.406250   3.687500   2.812500 
#> 
#> [[2]]
#> [[2]][[1]]
#>        mpg        cyl       disp         hp       drat         wt       qsec 
#>  20.090625   6.187500 230.721875 146.687500   3.596562   3.217250  17.848750 
#>         vs         am       gear       carb 
#>   0.437500   0.406250   3.687500   2.812500 
#> 
#> [[2]][[2]]
#>        mpg        cyl       disp         hp       drat         wt       qsec 
#>  20.090625   6.187500 230.721875 146.687500   3.596562   3.217250  17.848750 
#>         vs         am       gear       carb 
#>   0.437500   0.406250   3.687500   2.812500 
#> 
#> 
unlist2d(rapply2d(l, fmean))
#>   .id.1 .id.2      mpg    cyl     disp       hp     drat      wt     qsec
#> 1     1    NA 20.09062 6.1875 230.7219 146.6875 3.596562 3.21725 17.84875
#> 2     2     1 20.09062 6.1875 230.7219 146.6875 3.596562 3.21725 17.84875
#> 3     2     2 20.09062 6.1875 230.7219 146.6875 3.596562 3.21725 17.84875
#>       vs      am   gear   carb
#> 1 0.4375 0.40625 3.6875 2.8125
#> 2 0.4375 0.40625 3.6875 2.8125
#> 3 0.4375 0.40625 3.6875 2.8125