CODEWITHSUNDEEP
r
dasds
dasds

Reputation: 170

How to save structure of a complex list in R

I have a pretty long nested list in R. My goal is to get an overview of the structure, i.e. variable names and optionally variable types (like int, chr etc.). I want to save this structure in a spreadsheet to show it to non-data people so that they understand which data we have available.

here is an example of a simplified nested list.

my_list <- list(
  a = c(1,2,3),
  b = list(
    c = data.frame(
      d = c(1,2),
      e = c("a", "b")
      )
    ),
      f = list(
        g = rep(1,10),
        h = "a"
      )
)

str(my_list)
List of 3
 $ a: num [1:3] 1 2 3
 $ b:List of 1
  ..$ c:'data.frame':   2 obs. of  2 variables:
  .. ..$ d: num [1:2] 1 2
  .. ..$ e: Factor w/ 2 levels "a","b": 1 2
 $ f:List of 2
  ..$ g: num [1:10] 1 1 1 1 1 1 1 1 1 1
  ..$ h: chr "a"

so my goal is to have a tidy overview of the structure within my list. Similar to a database structure. I tried to save the str output in a variable via structure <- capture.output(str(my_list)) but this did not help me.

One example of an output can be:

  names values
1     a    num
2     d    num
3     e    chr
4     g    num
5     h    chr

Upvotes: 1

Views: 350

Answers (1)

s_baldur
s_baldur

Reputation: 33498

Here is an idea:

struct <- rapply(my_list, class)
struct <- data.frame(
  address = gsub(".", ">", names(struct), fixed = TRUE), 
  type    = unname(struct)
)
struct

#   address      type
# 1       a   numeric
# 2   b>c>d   numeric
# 3   b>c>e    factor
# 4     f>g   numeric
# 5     f>h character

Upvotes: 2

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