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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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 > > -- > ---------------------------------------- > La mia Cartella di Posta in Arrivo ? protetta da SPAMfighter > 259 messaggi contenenti spam sono stati bloccati con successo. > Scarica gratuitamente SPAMfighter! > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html >-- Chuck Cleland, Ph.D. NDRI, Inc. 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 452-1424 (M, W, F) fax: (917) 438-0894
Hi,
this should work fine:
subset <- c(2,3)
for (n in subset) {
cat(n,":",matrixX[as.integer(vectorY[row(vectorY)==n]),])
}
Good luck
Bart
Original message:
From: Roberto Furlan <roberto.furlan_at_gmail.com>
Date: Sun 19 Mar 2006 - 04:47:47 EST
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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