How to get the ouput of my result in json in R

Question

Hi i am using R with opencpu.right now i used jsonlite library to get my results in json format but unforutnately it fails. I got the output like this.

["A101 Prateek Wisteria Sector 77 Noida New Delhi","7780274.18056666","1"]

i want the output the output like this

{ "flag": "0", "property_details", "<<address>>", "estimate", "<<estimated value from R>>" }

here is my program

library(jsonlite)
delhi <- read.delim("delhi.tsv", na.strings = "") 
delhi$lnprice <- log(delhi$price)
if(address1 %in% delhi$property_address_1)
{

    data <- read.delim("UItest.txt", na.strings = "")
    heddel <- lm(lnprice ~ bedrooms+ area+ bathrooms, data = delhi)
    result <- predict(heddel,data)
    final_prediction = exp(result)
    property_details = address1
    property_details
    flag=1 
    estimated_value <- final_prediction
    result <- c(property_details,estimated_value,flag)
    col_headings <- c('property_details','estimated_value','flag')
    names(result) <- col_headings
    toJSON(result,Pretty=TRUE)
    }

any help will be appreciated.

Answer 1

To get output resembling your desired result try defining your results variable as a data.frame rather than a named vector .

Using some fictitious data on the key lines from your code:

> library(jsonlite)
> result <- c("xyz",123.45,1)
> col_headings <- c('property_details','estimated_value','flag')
> names(result) <- col_headings
> toJSON(result, pretty=TRUE)
["xyz", "123.45", "1"] 

Now refactoring this code a little bit to use a data.frame instead of a named vector :

> result <- data.frame('property_details'="xyz",'estimated_value'=123.45,'flag'=1)
> toJSON(result,pretty=TRUE)
[
  {
    "property_details": "xyz",
    "estimated_value": 123.45,
    "flag": 1
  }
] 

This also has the side effect of not coercing integer and numeric values into character strings.

Answer 2

You need to "transpose" the results. Consider:

library(jsonlite)
col_headings <- c('property_details','estimated_value','flag')
result <- c("PropDetails", 1.1, TRUE)
results=data.frame(t(result))
names(results)=col_headings

Then:

toJSON(results)

produces:

[{"property_details":"PropDetails","estimated_value":"1.1","flag":"TRUE"}]