Extracting data from a list of lists into its own `data.frame` with `purrr`

Question

Representative sample data (list of lists):

l <- list(structure(list(a = -1.54676469632688, b = \"s\", c = \"T\", 
d = structure(list(id = 5L, label = \"U         


        

Answer 1

For more information on purrr, I recommend Grolemund and Wickham's "R for Data Science" http://r4ds.had.co.nz/

I think one issue you are facing is that some of the items in l$d are lists of variables with one observation each, ready to be converted to data frames, while other items are lists of such lists.

But I'm not that good at purrr myself. Here's how I would do it:

l <- lapply(l, function(x){x$d}) ## work with the data you need.

list_of_observations <- Filter(function(x) {!is.null(names(x))},l)

list_of_lists <- Filter(function(x) {is.null(names(x))}, l)

another_list_of_observations <- unlist(list_of_lists, recursive=FALSE)

df <- lapply(c(list_of_observations, another_list_of_observations),
             as.data.frame) %>% bind_rows