Thanks Michael, This seems to get me half-way towards a solution. However, I am still having some difficulty in getting the out.csv exactly as I would like. I should probably explain the issue a bit further.
I am reading in a csv file containing a list of 'n' parameters. I have attached a csv ( http://r.789695.n4.nabble.com/file/n4630928/read.csv read.csv ) which contains 10 parameters as an example. However, the final problem may have up to 2000 parameters. Currently, these have string titles in the first column. However, I can change these to numbers if it causes problems in R. As you said correctly, this will give me a data.frame with mean and sd values. The problem I have is in the creation of the matrix of rnorm values. Using the for loop specified, I am getting a single column with the rnorm values for the last parameter specified (see attached http://r.789695.n4.nabble.com/file/n4630928/out.csv out.csv ). Re-running the for loop appends another column to the csv file, below the original column. I have attached an example of the output I am looking for ( http://r.789695.n4.nabble.com/file/n4630928/OutputSample.csv OutputSample.csv ). I believe, the approach here is correct, I just need to make a few modifications to the for loop. This also needs to be scalable to allow for the inclusion of multiple paramters (up to 2000) and samples (up to 1 million). I will look into the dataConnections process you mentioned to address this task. Also, just in case the above attachments don't work, here is a link to the shared files on Google Drive: https://docs.google.com/open?id=0Bwwrh1DeZXteSFBXNVI1NGZfQjg Thanks again for the help. Very much appreciated. -- View this message in context: http://r.789695.n4.nabble.com/RNORM-matrix-based-on-CSV-file-values-for-MEAN-and-SD-tp4630901p4630928.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.