Writing dictionary addition function in R-CodePudding

I need to write the equivalent of the following code in R but I'm not quite sure how to go about it:

def add(args):
  result = args["a"]   args["b"]
  return result

The reason why is because for the platform I am using (Cloudera Data Science Workbench) models need a JSON input to be able to call them using an API key

So if I write a test model in R such as:

f <- function(x, y) {
    return (x   y)
}

I cannot do a call like {"x" : 2, "y" : 4} using the httr package.

So I either need to make a dictionary like call for functions in R

I am simply calling JSON incorrectly in which case could someone help me format that correctly for an API call

Thanks

CodePudding user response：

JSON is the default data format for most REST APIs. We can serialize an R list to JSON using the jsonlite package. The other way of creating an R list based on a json string is also possible:

library(jsonlite)

# named lists
l <- list(x = 2, y = 4)
l
#> $x
#> [1] 2
#> 
#> $y
#> [1] 4
c <- "{\"x\":3,\"y\":5}"
c
#> [1] "{\"x\":3,\"y\":5}"

toJSON(l, auto_unbox = TRUE)
#> {"x":2,"y":4}
fromJSON(c, simplifyVector = TRUE)
#> $x
#> [1] 3
#> 
#> $y
#> [1] 5

# vector without names
toJSON(c(1,2,3), auto_unbox = TRUE)
#> [1,2,3]
fromJSON("[4,5,6]", simplifyVector = TRUE)
#> [1] 4 5 6

^{Created on 2021-10-07 by the reprex package (v2.0.1)}

CodePudding user response：

Thanks @danlooo for the help. Along with my own research I came up with an answer that satisfies my question

As the rest API needs a key-value pair format on CSDW, I can do the following taken from @danlooos answer:

f <- function(l) {
    return (l$a   l$b)
}

f(list(a = 2, b = 3) # Returns 5

This can be put into JSON format then for the API call as:

{"a" : 2, "b" : 3}