On 10/30/2009 06:12 AM, Federico Abascal wrote:
Hi,
I am investigating a problem for which I found no solution.
I have a matrix with two columns. I have plotted it as an x-y plot
(plot(matrix[,1],matrix[,2])
But this is not apropriate for my purposes. I need to group the data
in matrix[,1] into groups (as an histogram would do). Then I have to
calculate the average of matrix[,2] for each group.
Before starting with loops and loops I would like to know if is there
some way to do this easily with R.
Hi Federico,
If I understand your problem, I think you want first to use "cut":
groups<-cut(matrix[1,],breaks=???)
where ??? is the vector of breakpoints that you want. Then you can use
whatever averaging function (AVEFUN) you want with something like "by":
by(matrix[,2],groups,AVEFUN)
Jim
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