json - Continuing a while loop after error in R -

i trying use while loop download bunch of json files.

they numbered 255 1. however, of them missing (for example, 238.json not exist).

scheduleurl <- "http://blah.blahblah.com/schedulejsonfile=" <- 255 while ( > 0) {      last = paste0(as.character(i), ".json")     path = "/users/user/desktop/temp"     fullpath = paste0(path, last)     ithscheduleurl <- paste0(scheduleurl, as.character(i))     download.file(ithscheduleurl, fullpath)     <- - 1     } 

i want write while loop such if encounters nonexisting file (as when = 238), continues 237 instead of stopping.

i tried trycatch() function way, didn't work (keeps trying same url) :

while ( > 0) {     possibleerror <- trycatch({     last = paste0(as.character(i), ".json")     path = "/users/dlopez/desktop/temp"     fullpath = paste0(path, last)     ithscheduleurl <- paste0(scheduleurl, as.character(i))     download.file(ithscheduleurl, fullpath)     <- - 1}     , error=function(e) e)       if(inherits(possibleerror, "error")) {             next     } } 

any appreciated!

url.exists rcurl package should trick.

library(rcurl)  while ( > 0) {  last = paste0(as.character(i), ".json") path = "/users/user/desktop/temp" fullpath = paste0(path, last) ithscheduleurl <- paste0(scheduleurl, as.character(i)) if (url.exists(ithscheduleurl)) { download.file(ithscheduleurl, fullpath) } <- - 1 }