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The rjson::fromJSON() reads a file incorrectly while jsonlite::fromJSON() reads it fine. Here's a sample example.

file test.json contents:

{"name": "Sanjay",

"unit_price": 130848,

"amount": 11,

"up_to_data_sales": 45725}

the jsonlite fromJSON outputs:

jsonlite::fromJSON("test.json")

$name

[1] "Sanjay"



$unit_price

[1] 130848



$amount

[1] 11



$up_to_data_sales

[1] 45725

But the same throws an error in rjson package.

rjson::fromJSON("test.json") 



Error in rjson::fromJSON("test.json") :   parseTrue: expected to see 'true' - likely an unquoted string starting with 't'.

1. Why is this error coming?


2. What is the reason rjson package was launched when jsonlite existed?

Well:

stringdist::stringdist("rjson", "jsonlite")

## [1] 5

That's a modest difference to begin with.

However, your assertion seems to be amiss:

library(magrittr)



rjson::fromJSON('{"name": "Sanjay",

"unit_price": 130848,

"amount": 11,

"up_to_data_sales": 45725}') %>% str()

## List of 4

##  $ name            : chr "Sanjay"

##  $ unit_price      : num 130848

##  $ amount          : num 11

##  $ up_to_data_sales: num 45725



jsonlite::fromJSON('{"name": "Sanjay",

"unit_price": 130848,

"amount": 11,

"up_to_data_sales": 45725}') %>% str()

## List of 4

##  $ name            : chr "Sanjay"

##  $ unit_price      : int 130848

##  $ amount          : int 11

##  $ up_to_data_sales: int 45725

Apart from jsonlite using a more diminutive data type for the numbers, they both parse the JSON fine.

So there's an issue with your file that you failed to disclose in the question.

A further incorrect assertion

-rw-rw-r--  1 bob  staff      2690 Jul 30  2007 rjson_0.1.0.tar.gz

-rw-rw-r--  1 bob  staff    400196 Dec  3  2013 jsonlite_0.9.0.tar.gz

not to mention:

-rw-rw-r--  1 bob   staff   873843 Oct  4  2010 RJSONIO_0.3-1.tar.gz

rjson came first. (dir listings came from the CRAN mirror sitting next to me).

You can actually read about the rationale and impetus behind jsonlite here: https://arxiv.org/abs/1403.2805 (which I got off the CRAN page for jsonlite.

This is an answer for the question asked but not for the example

There is a difference in the way they read files:

For example consider the following input:

{
"id": 1,
"prod_info": [
{
"product": "xyz",
"brand": "pqr",
"price": 500
},
{
"product": "abc",
"brand": "klm",
"price": 5000
}
]
}

prod_info in the above input is a list with 2 vectors. But jsonlite reads it in the form of dataframe while rjson reads it as a list

x <- jsonlite::fromJSON("input.json")

y <- rjson::fromJSON(file = "Input.json") #rjson does not read the file if 'file=' command is not given

Outputs:

x

$id

[1] 1



$prod_info

  product brand price

1     xyz   pqr   500

2     abc   klm  5000



y

$id

[1] 1



$prod_info

$prod_info[[1]]

$prod_info[[1]]$product

[1] "xyz"



$prod_info[[1]]$brand

[1] "pqr"



$prod_info[[1]]$price

[1] 500





$prod_info[[2]]

$prod_info[[2]]$product

[1] "abc"



$prod_info[[2]]$brand

[1] "klm"



$prod_info[[2]]$price

[1] 5000



class(x$prod_info)

[1] "data.frame"



class(y$prod_info)

[1] "list"