CODEWITHSUNDEEP
rjsondataframe
Brayn
Brayn

Reputation: 416

Mapping leveled items from a JSON list into a data frame in R

I have a data frame on trending YouTube videos that has an integer column category_id representing the ID of the video category. This ID is stored in a seperate .json file like that looks like:

{
"items": [
  {
   "kind": "youtube#videoCategory",
   "etag": "\"m2yskBQFythfE4irbTIeOgYYfBU/Xy1mB4_yLrHy_BmKmPBggty2mZQ\"",
   "id": "1",
   "snippet": {
    "channelId": "UCBR8-60-B28hp2BmDPdntcQ",
    "title": "Film & Animation",
    "assignable": true
    }
  },
  {
    etc..
  }
 ]
}

As you can see the "id" is defined in the first level of the file and I would also need "title" through snippet { }. I have imported the JSON data into R with the rjson library as follows:

library(rjson)
json_list <- fromJSON(file = "C:\\...\\US_category_id.json")

Which returns a list object of 1. When I try to turn this into a data frame through json_df <- as.data.frame(json_list$items) it returns a flat data frame of one row and a bunch of columns.

What is the best practice here to return a data frame on the .json file containing the "id" and "title" so I can combine it with my other data frame down the line?

Here's what the list object of 1 looks like in RStudio enter image description here

Upvotes: 0

Views: 146

Answers (1)

ekoam
ekoam

Reputation: 8844

Perhaps try:

pluck_json <- function(json, sel) {
  vapply(json, `[[`, character(1L), sel)
}

result <- data.frame(
  id = pluck_json(json_list$items, "id"), 
  title = pluck_json(json_list$items, c("snippet", "title"))
)

Upvotes: 1

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