How can I best flatten a nested list to a data.frame in R?

I would like to convert information from a rest api, which comes in form of json, to a data.frame. The list is nested and theoretically I could repeatedly call purrr::flatten() to get to the bottom of the list and then extract the information using for example purrr:::map_dfr and magrittr:::extract. However, this is very domain specific and doesn't work nicely when extracting information from multiple "hierarchies". I have the following set-up in R:

library(rjson)

url <- "https://api3.geo.admin.ch/rest/services/api/SearchServer?searchText=Avenue de Lavaux 63, 1009 Pully&origins=address&type=locations"
result <- rjson::fromJSON(file = URLencode(url))

Two questions arise:

How can I nicely extract attributes like detail, x and y and write them to a data.frame?
On top of that, how can I directly extract values by their names. That is how to extract the values for weight, x, y, and detail.

Thank you very much.

Solution

You can unlist the result and extract x and y like this:

res <- unlist(result)
res['results.attrs.x']
# results.attrs.x 
#  "151398.09375"

res['results.attrs.y']
# results.attrs.y 
#  "540429.3125"

You can get the names of all other values like this:

names(res)
#[1] "results.id"  "results.weight"  "results.attrs.origin"         
#    "results.attrs.geom_quadindex" "results.attrs.zoomlevel"     
#[6] "results.attrs.featureId" "results.attrs.lon" "results.attrs.detail"   
#    "results.attrs.rank" "results.attrs.geom_st_box2d" "results.attrs.lat"
#    "results.attrs.num" "results.attrs.y" "results.attrs.x"  "results.attrs.label"

Then you can combine them in a dataframe:

res_df <- data.frame(
  X = res['results.attrs.x'],
  Y = res['results.attrs.y']
)