Question

Right now I have the lines:

envCache <- new.env( hash=TRUE, parent = .GlobalEnv )
print(parent.env(envCache))

R claims the environment is in the global environment, but when I try to find the environment later it’s not there.

What I’m trying to do here is cache some dataframes in and environment under the global environment, so each time I call a function it does not have to hit the server to get the same data again. Ideally, I’ll call the function once using a source command in the R console, it will grab the data necessary, save it to an environment in the global environment, and then when I call the same function from the R console it will see the environment and dataframe from which it will grab the data as opposed to re-querying the server.

Answer 1

Here’s what I came up with as an alternate solution. It may be doing the same thing as the other answer in the backround, but the code is more intuitive to me.

cacheTesting <- function()
{
    if (exists("cache"))
    { 
        print("IT WORKS!!!") 
        cacheData <- get("test", envir = cache)
        print(cacheData)
    }
    else
    {   
        assign("cache", new.env(hash = TRUE), envir = .GlobalEnv) 
        test <- 42
        assign("test", test, envir = cache) 
    }
}

The first run of the code creates the environment in the .GlobalEnv using an assign statement. The second run sees that environment, because it actually made it to .GlobalEnv, and pulls the data placed there from it before printing it.