Constructing request payload in R using rjson/jsonlite - json

Question

My current code as seen below attempts to construct a request payload (body), but isn't giving me the desired result.
library(df2json)
library(rjson)
y = rjson::fromJSON((df2json::df2json(dataframe)))
globalparam = ""
req = list(
Inputs = list(
input1 = y
)
,GlobalParameters = paste("{",globalparam,"}",sep="")#globalparam
)
body = enc2utf8((rjson::toJSON(req)))
body currently turns out to be
{
"Inputs": {
"input1": [
{
"X": 7,
"Y": 5,
"month": "mar",
"day": "fri",
"FFMC": 86.2,
"DMC": 26.2,
"DC": 94.3,
"ISI": 5.1,
"temp": 8.2,
"RH": 51,
"wind": 6.7,
"rain": 0,
"area": 0
}
]
},
"GlobalParameters": "{}"
}
However, I need it to look like this:
{
"Inputs": {
"input1": [
{
"X": 7,
"Y": 5,
"month": "mar",
"day": "fri",
"FFMC": 86.2,
"DMC": 26.2,
"DC": 94.3,
"ISI": 5.1,
"temp": 8.2,
"RH": 51,
"wind": 6.7,
"rain": 0,
"area": 0
}
]
},
"GlobalParameters": {}
}
So basically global parameters have to be {}, but not hardcoded. It seemed like a fairly simple problem, but I couldn't fix it. Please help!
EDIT:
This is the dataframe
X Y month day FFMC DMC DC ISI temp RH wind rain area
1 7 5 mar fri 86.2 26.2 94.3 5.1 8.2 51 6.7 0.0 0
2 7 4 oct tue 90.6 35.4 669.1 6.7 18.0 33 0.9 0.0 0
3 7 4 oct sat 90.6 43.7 686.9 6.7 14.6 33 1.3 0.0 0
4 8 6 mar fri 91.7 33.3 77.5 9.0 8.3 97 4.0 0.2 0
This is an example of another data frame
> a = data.frame("col1" = c(81, 81, 81, 81), "col2" = c(72, 69, 79, 84))

Answer 1

Using this sample data
dd<-read.table(text=" X Y month day FFMC DMC DC ISI temp RH wind rain area
1 7 5 mar fri 86.2 26.2 94.3 5.1 8.2 51 6.7 0.0 0", header=T)
You can do
globalparam = setNames(list(), character(0))
req = list(
Inputs = list(
input1 = dd
)
,GlobalParameters = globalparam
)
body = enc2utf8((rjson::toJSON(req)))
Note that globalparam looks a bit funny because we need to force it to a named list for rjson to treat it properly. We only have to do this when it's empty.