How do I check the existence of a downloaded file

Question

I\'ve created a R markdown file that starts by loading a file from the web. I found the cache=TRUE to be a little flaky so I want to put an if condition in to check for the

Answer 1

As per the answer given by @agstudy

 destfile="./data/samsungData.rda" 
 fileURL <-
 "https://dl.dropbox.com/u/7710864/courseraPublic/samsungData.rda"   
 if (!file.exists(destfile)) {
    setInternet2(TRUE)
    download.file(fileURL ,destfile,method="auto") }
    load("./data/samsungData.rda")
 }
 load(destfile)