How to merge 2 json objects in R?

Question

I've got 2 json objects and want to merge them into one unique objects in R.

Here the content of files:

object 1:

{
    "value": [
        "1",
        "2",
        "3"
    ]
}

object 2:

{
    "value": [
        "4",
        "5",
        "6"
    ]
}

expected results

{
    "value": [
        "1",
        "2",
        "3",
        "4",
        "5",
        "6"
    ]
}

I found similar questions in other language (such as this question), but I 'd like to do that in R (and I use jqr package).

Do you have any idea? Thank you.

Convert to data frames using `jsonlite::fromJSON`, combine, convert back to JSON with `jsonlite::toJSON`. — Gregor Thomas, Apr 26 '18 at 03:12

Maurits Evers · Accepted Answer · 2018-04-26T03:28:38.563

To demonstrate @Gregor's advice, here is an example.

# Store JSON content as lists (lst1, lst2)
library(jsonlite);   
lst1 <- fromJSON(txt =
    '{
    "value": [
        "1",
        "2",
        "3"
    ]
}')    
lst2 <- fromJSON(txt =
    '{
    "value": [
        "4",
        "5",
        "6"
    ]
}')

# Merge lst1 and lst2 and output as JSON
toJSON(Map(c, lst1, lst2))
#{"value":["1","2","3","4","5","6"]}

Note, this works for the sample data you provide; if you have multiple keys (perhaps with some keys present in one JSON but not the other), you need to adjust your combination/merging strategy.

score 4 · Answer 2 · answered Apr 26 '18 at 05:14

I'm still getting my head around jqr too so there is likely a better, more concise solution without needing the extra paste at the end.

jqr::jq(paste0(js1, js2), ".value[]") %>%     ## extract the 'value's
  combine() %>%                               ## combine to a single JSON
  paste0('{"value":', .,"}")                  ## construct output

  # [1] "{\"value\":[\"1\", \"2\", \"3\", \"4\", \"5\", \"6\"]}"

How to merge 2 json objects in R?

2 Answers2