riterationnested-liststype-coercion

Convert chararacter numbers to numeric in nested list with mixed types in R

I have a bunch of nested lists that arrive with all character-typed elements. Some of these characters are in fact numbers that need to be converted to numeric-typed elements.

How can I modify these lists so that all possible character-typed numbers are converted to numeric, but the non-number character elements remain intact (e.g., aren't converted to NA by as.numeric())?

For example, I start with

raw_list <- list(
      'a' = list('1', '2'),
      'b' = list(
        'c' = list('3', 'x'),
        'd' = c('4', 'z'),
        'e' = '5'))

But I need to get to

cleaned_list <- list(
      'a' = list(1, 2),
      'b' = list(
        'c' = list(3, 'x'),
        'd' = c('4', 'z'),
        'e' = 5))

Bonus: Extra gratitudie for tidyverse/purrr-based solutions

Solution

  • Another option is to use type.convert, which can take lists as arguments.

    raw_list %>%
  type.convert(as.is = TRUE)

    This would be the same as using purrr with type.convert.

    library(purrr)

purrr::map(raw_list, type.convert, as.is = TRUE)

    Output

    $a
$a[[1]]
[1] 1

$a[[2]]
[1] 2


$b
$b$c
$b$c[[1]]
[1] 3

$b$c[[2]]
[1] "x"


$b$d
[1] "4" "z"

$b$e
[1] 5