[R] extraction - subsets

[Chuck Cleland]

matrixX[vectorY %in% subsample,]

?"%in%"

Roberto Furlan wrote:
> Hi everybody,
> let us assume i have the following matrixX and vectorY
> 
> matrixX <- runif(100)
> dim(matrixX) <- c(10,10)
> vectorY <- as.matrix(as.character(seq(1,10)))
> 
> if I define:
> subsample<-c("2")
> 
> i can extract the rows from matriX based on the elements in vectorY which
> are listed in subsample
> matrixX[vectorY==subsample]
> 
> if I define subsample with more than 1 element, such as:
> subsample=c("2", "3")
> 
> how can i extract the rows from matriX based on the elements in vectorY
> which are listed in subsample?
> 
> many thanks
> 
> Roberto Furlan
> University of Turin
> 
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-- 
Chuck Cleland, Ph.D.
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