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Convert JSON To R

fromJSON.Rd

Convert a JSON object into an R object.

Usage

fromJSON( json_str, file, method = "C", unexpected.escape = "error", simplify = TRUE )

Arguments

json_str

a JSON object to convert

file

the name of a file to read the json_str from; this can also be a URL. Only one of json_str or file must be supplied.

method

use the C implementation, or the older slower (and one day to be depricated) R implementation

unexpected.escape

changed handling of unexpected escaped characters. Handling value should be one of "error", "skip", or "keep"; on unexpected characters issue an error, skip the character, or keep the character

simplify

If TRUE, attempt to convert json-encoded lists into vectors where appropriate. If FALSE, all json-encoded lists will be wrapped in a list even if they are all of the same data type.

Value

R object that corresponds to the JSON object

See also

toJSON

Examples


fromJSON('[1,2,3]', simplify=TRUE)
#> [1] 1 2 3
# returns c(1,2,3)
fromJSON('[1,2,3]', simplify=FALSE)
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 2
#> 
#> [[3]]
#> [1] 3
#> 
# returns list(1,2,3)

#As a result, this will output "1"
toJSON(fromJSON('[1]', simplify=TRUE))
#> [1] "1"
#Compared with this which will output "[1]" as expected
toJSON(fromJSON('[1]', simplify=FALSE))
#> [1] "[1]"

#R vs C execution time
x <- toJSON( iris )
system.time( y <- fromJSON(x) )
#>    user  system elapsed 
#>   0.001   0.000   0.001 
system.time( y2 <- fromJSON(x,method = "R") )
#>    user  system elapsed 
#>    0.02    0.00    0.02