subset an additional variable and append it to the previous one in R

Question

I have a function that subsets what (i.e., a variable) user requests out of this dataset.

The function works perfect. But I was wondering if there might be a way that in addition to what user requests, the function always subset entries that contain control == TRUE and append those to what the user has requested.

For example, suppose user wants to subset entries with type == 4. In this dataset, there are 4 such entries. As reproducible code and data below show, this is done easily BUT there also are 4 other entries for which control == TRUE, how can function find and append these 4 other entries to its currently-producible output?

foo <- function(List, what){       ## The subsetting function

  s <- substitute(what) 

  h <- lapply(List, function(x) do.call("subset", list(x, s)))

  Filter(NROW, h)
}


D <- read.csv("https://raw.githubusercontent.com/izeh/i/master/k.csv", h = T) ## Dataset
L <- split(D, D$study.name) ; L[[1]] <- NULL   ## list by `study.name`

foo(L, type == 4)    ## subsets entries with `type == 4`. BUT how can function `foo` 
                     ## find and append entries with `control == TRUE` to its output?

Answer 1

After Filtering the list elements ('h1'), subset those same elements from the original list where the 'control' is TRUE (logical column) and theen rbind the corresponding list elements with Map

foo <- function(List, what){     
   s <- substitute(what) 
   h <- lapply(List, function(x) do.call("subset", list(x, s)))
   h1 <- Filter(NROW, h)      
   h2 <- lapply(List[names(h1)], function(x) subset(x, control))
   Map(rbind, h1, h2)      
}


foo(L, type == 4)
#$Mubarak
#   study.name  group.name  n  d t.pair df mdif sdif  mpre sdpre  mpos sdpos      r rev.sign autoreg post control outcome ESL prof
#43    Mubarak   grA.short 17 NA  4.366 NA   NA   NA    NA    NA    NA    NA     NA    FALSE   FALSE    1   FALSE       1   2   NA
#44    Mubarak    grA.long 17 NA     NA NA   NA   NA 0.395 0.280 0.520 0.205 0.6737    FALSE   FALSE    2   FALSE       1   2   NA
#54    Mubarak  grB.shortB 16 NA  7.864 NA   NA   NA    NA    NA    NA    NA     NA     TRUE   FALSE    1   FALSE       2   2   NA
#55    Mubarak   grB.longB 16 NA     NA NA   NA   NA 0.105 0.030 0.056 0.025 0.5618     TRUE   FALSE    2   FALSE       2   2   NA
#47    Mubarak  Cont.short 13 NA  0.401 NA   NA   NA    NA    NA    NA    NA     NA    FALSE   FALSE    1    TRUE       1   2   NA
#48    Mubarak   Cont.long 13 NA     NA NA   NA   NA 0.545 0.272 0.436 0.204 0.5320    FALSE   FALSE    2    TRUE       1   2   NA
#49    Mubarak  Cont.short 13 NA  0.401 NA   NA   NA    NA    NA    NA    NA     NA    FALSE   FALSE    1    TRUE       1   2   NA
#50    Mubarak   Cont.long 13 NA     NA NA   NA   NA 0.545 0.272 0.436 0.204 0.5320    FALSE   FALSE    2    TRUE       1   2   NA
#56    Mubarak Cont.shortB 13 NA  2.793 NA   NA   NA    NA    NA    NA    NA     NA     TRUE   FALSE    1    TRUE       2   2   NA
#57    Mubarak  Cont.longB 13 NA     NA NA   NA   NA 0.093 0.032 0.078 0.032 0.9159     TRUE   FALSE    2    TRUE       2   2   NA
#   scope type
#43     2    4
#44     2    4
#54     2    4
#55     2    4
#47     2    2
#48     2    2
#49     2    2
#50     2    2
#56     2    2
#57     2    2