[R] Mutliple sets of data in one dataset....Need a loop?

[David Winsemius]

On Jan 20, 2010, at 11:07 AM, BioStudent wrote:

>
> Hi
>
> I'm hoping someone can help me I am a relative newbie to R.
>
> I have data that is in a similar format to this...
>
> Experiment Score1 Score2
> X -0.85 -0.02
> X -1.21 -0.02
> X  1.05  0.09
> Y -1.12 -0.07
> Y -0.27 -0.07
> Y -0.93 -0.08
> Z 1.1 -0.03
> Z 2.4 0.09
> Z -1.0 0.09
>
> Now I can easily have a look at the overall correlation of score 1  
> and 2 by
> doing this
> plot(data[,2], data[,3])   or
> fit <- lm(data[,2] ~ data[,3]
>
> BUT! I really want to look at the correlations within each  
> experiment type
> so ideally a multiple plot per page of each correlation within an  
> experiment
> - and/or a way of looping through the data to get the simple linear
> regression for each experiment for scores 1 and 2. This looks like  
> an easy
> example but I have thousands of results so it would be really hand  
> to find
> away of doing this quickly!!

library(lattice)
?xyplot  # a group specification
?panel.lmline

There are quite a few examples at the xyplot help page.

>
-- 

David Winsemius, MD
Heritage Laboratories
West Hartford, CT