Say I have a nested list
tmp <- list(
a = 1,
list(list(x = 1, y = "a"), list(z = 2)),
mtcars[1:3, ],
list(mtcars[4:6, ], mtcars[7:10, ])
)
I want to replicate what rlang::flatten() does.
> rlang::flatten(tmp)
$a
[1] 1
[[2]]
[[2]]$x
[1] 1
[[2]]$y
[1] "a"
[[3]]
[[3]]$z
[1] 2
[[4]]
mpg cyl disp hp drat wt qsec vs am gear carb
Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
[[5]]
mpg cyl disp hp drat wt qsec vs am gear carb
Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
[[6]]
mpg cyl disp hp drat wt qsec vs am gear carb
Duster 360 14.3 8 360.0 245 3.21 3.57 15.84 0 0 3 4
Merc 240D 24.4 4 146.7 62 3.69 3.19 20.00 1 0 4 2
Merc 230 22.8 4 140.8 95 3.92 3.15 22.90 1 0 4 2
Merc 280 19.2 6 167.6 123 3.92 3.44 18.30 1 0 4 4
i.e. I want to bring everything up one level. Reduce(c, tmp) almost gets me there but not quite.
It would seem as though this function does what I need
flatten <- function(lst) {
nested <- vapply(lst, function(x) inherits(x[1L], "list"), FALSE)
res <- c(lst[!nested], unlist(lst[nested], recursive = FALSE))
if (sum(nested)) Recall(res) else return(res)
}