Parse JSON with R

Question

I am fairly new to R, but the more use it, the more I see how powerful it really is over SAS or SPSS. Just one of the major benefits, as I see them, is the ability to get and analyze data from the web. I imagine this is possible (and maybe even straightforward), but I am looking to parse JSON data that is publicly available on the web. I am not a programmer by any stretch, so any help and instruction you can provide will be greatly appreciated. Even if you point me to a basic working example, I probably can work through it.

score 98 · Accepted Answer · edited Jan 12 '21 at 06:23

RJSONIO from Omegahat is another package which provides facilities for reading and writing data in JSON format.

rjson does not use S4/S3 methods and so is not readily extensible, but still useful. Unfortunately, it does not used vectorized operations and so is too slow for non-trivial data. Similarly, for reading JSON data into R, it is somewhat slow and so does not scale to large data, should this be an issue.

Update (new Package 2013-12-03):

jsonlite: This package is a fork of the RJSONIO package. It builds on the parser from RJSONIO but implements a different mapping between R objects and JSON strings. The C code in this package is mostly from the RJSONIO Package, the R code has been rewritten from scratch. In addition to drop-in replacements for fromJSON and toJSON, the package has functions to serialize objects. Furthermore, the package contains a lot of unit tests to make sure that all edge cases are encoded and decoded consistently for use with dynamic data in systems and applications.

I found [this comparison](http://rstudio-pubs-static.s3.amazonaws.com/31702_9c22e3d1a0c44968a4a1f9656f1800ab.html) of rjson, RJSONIO, and jsonlite helpful — Eric, Jan 27 '15 at 16:36
The comparison link above is dead. Is [this](https://rstudio-pubs-static.s3.amazonaws.com/31702_9c22e3d1a0c44968a4a1f9656f1800ab.html) the correct link? (the difference is https) — woodvi, Jun 09 '15 at 22:57

score 71 · Answer 2 · edited Mar 09 '21 at 23:24

71

The jsonlite package is easy to use and tries to convert json into data frames.

Example:

library(jsonlite)

# url with some information about project in Andalussia
url <- 'https://api.stackexchange.com/2.2/badges?order=desc&sort=rank&site=stackoverflow'

# read url and convert to data.frame
document <- fromJSON(txt=url)

edited Mar 09 '21 at 23:24

Abel Callejo

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answered Nov 23 '14 at 14:32

joscani

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This was incredibly easy to use for what I needed. Thank you so much – Unknown Coder Feb 04 '15 at 02:33
document <- fromJSON(file = url); #but the request times out – EngrStudent Feb 05 '16 at 19:04
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Love this. Seems much better than the clutter created by rjson. – randominstanceOfLivingThing Mar 05 '16 at 23:05
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Unless the original json format is already flattened, `jsonlite` is more or less as useful as a fork to eat soup. – gented Dec 07 '17 at 10:46

score 21 · Answer 3 · edited Sep 07 '13 at 16:57

21

Here is the missing example

library(rjson)
url <- 'http://someurl/data.json'
document <- fromJSON(file=url, method='C')

edited Sep 07 '13 at 16:57

MattBagg

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answered Oct 28 '12 at 10:57

Leeth

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this worked for me but you don't want to pass a string for the file variable name as shown. – mrjrdnthms Aug 06 '13 at 20:01

pauljeba · Answer 4 · 2016-01-11T06:49:26.750

The function fromJSON() in RJSONIO, rjson and jsonlite don't return a simple 2D data.frame for complex nested json objects.

To overcome this you can use tidyjson. It takes in a json and always returns a data.frame. It is currently not availble in CRAN, you can get it here: https://github.com/sailthru/tidyjson

Update: tidyjson is now available in cran, you can install it directly using install.packages("tidyjson")

score 2 · Answer 5 · answered Feb 26 '13 at 17:36

For the record, rjson and RJSONIO do change the file type, but they don't really parse per se. For instance, I receive ugly MongoDB data in JSON format, convert it with rjson or RJSONIO, then use unlist and tons of manual correction to actually parse it into a usable matrix.

score 1 · Answer 6 · edited Aug 31 '17 at 22:04

1

Try below code using RJSONIO in console

library(RJSONIO)
library(RCurl)


json_file = getURL("https://raw.githubusercontent.com/isrini/SI_IS607/master/books.json")

json_file2 = RJSONIO::fromJSON(json_file)

head(json_file2)

edited Aug 31 '17 at 22:04

SymbolixAU

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answered Aug 01 '17 at 08:28

Moby M

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Parse JSON with R

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