Don’t do it inside the loop. Make a list, then combine them outside the loop.
datalist = list()
for (i in 1:5) {
# ... make some data
dat <- data.frame(x = rnorm(10), y = runif(10))
dat$i <- i # maybe you want to keep track of which iteration produced it?
datalist[[i]] <- dat # add it to your list
}
big_data = do.call(rbind, datalist)
# or big_data <- dplyr::bind_rows(datalist)
# or big_data <- data.table::rbindlist(datalist)
This is a much more R-like way to do things. It can also be substantially faster, especially if you use dplyr::bind_rows
or data.table::rbindlist
for the final combining of data frames.