arrange multiple graphs using a for loop in ggplot2

Question

I want to produce a pdf which shows multiple graphs, one for each NetworkTrackingPixelId. I have a data frame similar to this:

> head(data)
  Net         


        

Answer 1

I recently had a project that required producing a lot of individual pngs for each record. I found I got a huge speed up doing some pretty simple parallelization. I am not sure if this is more performant than the dplyr or data.table technique but it may be worth trying. I saw a huge speed bump:

require(foreach)
require(doParallel)
workers <- makeCluster(4)
registerDoParallel(workers) 
foreach(i = seq(1, length(mtcars$gear)), .packages=c('ggplot2')) %dopar% {
  j <- qplot(wt, mpg, data = mtcars[i,])
  png(file=paste(getwd(), '/images/',mtcars[i, c('gear')],'.png', sep=''))
  print(j)
  dev.off()
}