CODEWITHSUNDEEP
rlistpurrr
MayaGans
MayaGans

Reputation: 1845

Create a named empty list based on dataframe and column names

I want create an empty list which takes on the name of a dataframe and has empty elements inside based on the name of the dataframe

What I've Tried - Does Not Work

my_list_function <- function(thedata) {
  list(
    x = map(names(x), ~ .x = list())
  ))
}

I want to be able to run 

my_list_function(mtcars)

and get the output:

Desired Output

list(
  mtcars = list(
    mpg = list(),
    cyl = list(),
    disp = list(),
    hp = list(),
    drat = list(),
    wt = list(),
    qseq = list(),
    vs = list(),
    am = list(),
    gear = list(),
    carb = list()
  )
)

Upvotes: 2

Views: 376

Answers (2)

akrun
akrun

Reputation: 887691

We can use setNames

my_list_function <- function(data) {
     nm1 <- deparse(substitute(data))
    setNames(list( setNames(rep(list(list()), length(data)), names(data))), nm1)
      }

my_list_function(mtcars)
#$mtcars
#$mtcars$mpg
#list()

#$mtcars$cyl
#list()

#$mtcars$disp
#list()

#$mtcars$hp
#list()
# ...

Or using purrr

library(purrr)
library(dplyr)
my_list_function <- function(data) {


   lst(!! enquo(data) := map(data, ~ list()))
  }
my_list_function(mtcars)
#$mtcars
#$mtcars$mpg
#list()

#$mtcars$cyl
#list()

#$mtcars$disp
#list()

#$mtcars$hp
#list()
# ...

Upvotes: 1

user10917479
user10917479

Reputation:

Using purrr:

library(purrr)
map(mtcars, ~ list())

If you want the name of the data itself in the list, you can try this:

my_list_function <- function(data) {
  .data <- rlang::enquo(data)

  list(map(data, ~ list())) %>% 
    set_names(rlang::as_name(.data))
}

my_list_function(mtcars)

Upvotes: 3

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