JSON to R: keep duplicate values

Question

I have a JSON data source that is a list of objects. Some of the properties of the object are themselves lists. I want to turn all this into a data frame, save lists as values ​​of a data frame .

Sample JSON data:

[{
    "id": "A",
    "p1": [1, 2, 3],
    "p2": "foo"
},{
    "id": "B",
    "p1": [4, 5, 6],
    "p2": "bar"
}]

Required data frame:

  id  p2      p1
1  A foo 1, 2, 3
2  B bar 4, 5, 6

Failed Attempt 1

I found this pretty easy way to parse my JSON:

unlisted_data <- lapply(fromJSON(json_str), function(x){unlist(x)})
data.frame(do.call("rbind", unlisted_data))

However, the unlisting process extends my duplicate value to multiple columns:

  id p11 p12 p13  p2
1  A   1   2   3 foo
2  B   4   5   6 bar

I expected the call unlistwith the option to recursive = FALSEtake care of this, but that is not the case.

Failed to try 2

I noticed that I can almost do this with a function I:

> data.frame(I(parsed_json[[1]]))
   parsed_json..1..
id                A
p1          1, 2, 3
p2              foo

. :

> t(data.frame(I(parsed_json[[1]])))
                 id  p1        p2   
parsed_json..1.. "A" Numeric,3 "foo"

Answer 1

jsonlite :

library(jsonlite)
fromJSON(txt)
#  id      p1  p2
#1  A 1, 2, 3 foo
#2  B 4, 5, 6 bar

fromJSON(txt)$p1
#[[1]]
#[1] 1 2 3
#
#[[2]]
#[1] 4 5 6