[R] extracting submatrix from a bigger one

Rui Barradas ruipbarradas at sapo.pt
Mon Jun 24 18:24:45 CEST 2013


Try the following.

result <- lapply(unique(dataset$ID), function(uid) dataset[dataset$ID == 
uid, ])
names(result) <- unique(dataset$ID)

Hope this helps,

Rui Barradas

Em 24-06-2013 15:36, matteo escreveu:
> Hi guys,
> I'm a newby, so sorry for the easy question.
> I have a matrix (459x28) in which a large number of observations are
> repeated (same placed sampled in different times).
> One of the columns is refers to the ID of the place of sampling.
> What I would like is to extract subset matrix for every point of sampling.
> I can do it manually, e.g. x1<-data.frame(dataset[dataset$ID=="x1",])
> but is it possible to write a script and let do it to R?
> So i got n submatrix of the n ID found in the original columns.
> Cheers
> Matteo
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