Loading 200MB JSON File into R - json

Question

I am trying to use R's rjson library to upload a 200MB JSON file into R , but I got the Cannot fit vector over 1KB error.
Here's the code I used to load the JSON file into R:
UnpackJSON <- function(filePath)
{
con <- file(filePath, "r")
input <- readLines(con, -1L)
# jsonData <- fromJSON(paste(input, collapse=""))
jsonData <- sapply(input, fromJSON)
close(con)
df <- data.frame(jsonData)
temp <- rownames(df)
df <- as.data.frame(t(df))
colnames(df) <- temp
rownames(df) <- NULL
return(df)
}
Is there a way to optimize this code or another way to load such a large file into R? I appreciate any input.

Answer 1

Why would you process the JSON data line per line using sapply? Couldn't you just say fromJSON(input)? I suspect a problem could be that the garbage collector waits for the entire sapply loop to finish before deleting any copies that are made in the analysis process (see also the comments here). So when vectorization does not work (which is greatly preferred), you could try and change the sapply loop to a for loop and see if that helps.