R: How to remove element from list by value or type

Question

I have a list containing lists and NAs. I'd like to filter the NAs out, but I don't know the exact name or position of the NAs.

I googled a lot, but only found how to remove elements by name or by indexing, but this is not what I'm looking for.

Here's an example of how my list looks like:

example <- list(list(1,2,3), list(2,3,4), NA, list(2,3,4))

My output looks like this:

Name      Type        Value
example   list[[4]]   List of length 4
  [[1]]   list[[3]]   List of length 3
  [[2]]   list[[3]]   List of length 3
  [[3]]   logical     NA               <-I'd like to remove this row
  [[4]]   list[[3]]   List of length 3

I'd like to write a loop that removes an element from my list if the value is "NA" or the type is "logical". Thanks in advance for your help!

Answer 1

It depends on your data structure. With your example, the following will work:

example[!is.na(example) & !is.logical(example)]

It becomes more complicated if the sub-lists can contain NA's that you want to remove as well.

Answer 2

You can use which function to find the index of NA elements and then remove them by index:

example[-which(is.na(example))]