> but I have thousands of results so it would be really hand to find away of > doing this quickly > its a little difficult to follow those examples
Given your data in data.frame DF, maybe add the following to your list to investigate : > dat = data.table(DF) > dat[, cor(Score1,Score2), by="Experiment"] Experiment V1 [1,] X 0.9889524 [2,] Y 0.3041195 [3,] Z -0.1346107 To do a plot instead just replace "cor" with "plot" or whatever else you want to do within each group. Since you said you have thousands of results, data.table is faster for that. In terms of ease of use, you could try plyr too, which you may well prefer. > those examples as all seem so different If you look and search crantastic, users are putting their comments there. That might help you make a decision more quickly and avoid you needing to post to r-help and wait for a reply, assuming there is a package that already does what you need. Searching the history of r-help would have found many solutions to your problem this time, but it seems you are looking for advice on the best way. This changes over time and depends on lots of factors, including what you really want to do. Once you have worked out which packages work best for you, put your votes/comments onto crantastic and it should help everyone who follows in your path. I guess you should then update your votes/comments as time progresses too. Btw, plyr is ranked #2 on crantastic and is designed specifically for your task !! Making yourself aware of the most popular packages would have helped you. If you need speed try data.table. When it comes to current, up to date advice on the most appropriate package, crantastic could be fantastic, assuming of course that you, the user, contributes to it. HTH "BioStudent" <s0975...@sms.ed.ac.uk> wrote in message news:1264072645590-1049653.p...@n4.nabble.com... > > Hi Thanks for all your help > > Its a little difficult to follow those examples as all seem so different > and > its hard to see how I do what I want to my data from the help files but > i'll > try... > -- > View this message in context: > http://n4.nabble.com/Mutliple-sets-of-data-in-one-dataset-Need-a-loop-tp1018503p1049653.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.