[R] r code
Jim Lemon
jim at bitwrit.com.au
Fri Jan 4 08:08:55 CET 2013
On 01/04/2013 02:03 AM, catalin roibu wrote:
> I have a problem. My data is now in this form:
> plot area d
> 1 0.01 34.6
> ...................
> 100 0.01 15.7
>
> First, I want to aggregate plots start from a plot in the center of sample
> (10 plots x 10 plots). I want to aggregate after the model plot1 in the
> center of area (0,01 m2), after increasing plot area with the near plots
> until the entire area (10000 m2). For a good explication I will attach a
> figure.
>
> Second, I want to aggregate plots starting to 1, 1, with 2 , 1 with 2 with
> 3 .....1 with 2 with 3........with 99 with 100.
> Third> I want to aggregate the values but choose random>Ex. 75, 9 with
> 83,......etc
> Thank you very much!
>
Hi catalin,
As your figure did not make it through to the list, I will have to do a
bit of guessing. Your data seem to be 100 samples, each 0.01 M2 in area.
These add up to 1 M2, so I'm not sure where the 10000 M2 comes from. The
aggregations are not that difficult, simply specify sets of indices and
use either the aggregate function you would like in a loop.
Assume that your data are in a data frame "mydata":
for(i in 1:100) cat("mean of 1:",i,mean(mydata[1:i,],na.rm=TRUE),"\n")
for(i in 1:100) {
ind<-sample(1:100,2)
cat("mean of",ind[1],"and",ind[2],mean(mydata[ind,],na.rm=TRUE]),"\n")
}
Jim
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