Thanks. I tried it and it worked wonderful.
Wishing for the "DAY' to come. Life needs to be 'reset'. --- On Wed, 7/15/09, Dimitris Rizopoulos <d.rizopou...@erasmusmc.nl> wrote: > From: Dimitris Rizopoulos <d.rizopou...@erasmusmc.nl> > Subject: Re: [R] (newbie) sum for certain number of rows > To: "kelvin lau" <kelvin...@yahoo.com> > Cc: r-help@r-project.org > Date: Wednesday, July 15, 2009, 6:25 PM > one way is the following: > > dat <- read.table(textConnection( > "0 0 1 0 0 1 0 1 > 0 0 0 0 0 0 0 0 > 1 0 0 1 1 0 1 0 > 0 0 1 1 0 0 0 0 > 1 1 0 0 0 0 1 1 > 0 0 0 0 0 0 0 0 > 0 1 0 1 1 0 1 0 > 1 1 1 1 1 1 1 1 > 1 1 1 1 1 1 1 1" > )) > closeAllConnections() > > k <- 3 > ind <- rep(seq(1, nrow(dat)/k), each = k) > rowsum(dat, ind) > > > I hope it helps. > > Best, > Dimitris > > > kelvin lau wrote: > > I have following data in a data.csv file separated by > space > > > > 0 0 1 0 0 1 0 1 > > 0 0 0 0 0 0 0 0 > > 1 0 0 1 1 0 1 0 > > 0 0 1 1 0 0 0 0 > > 1 1 0 0 0 0 1 1 > > 0 0 0 0 0 0 0 0 > > 0 1 0 1 1 0 1 0 > > 1 1 1 1 1 1 1 1 > > 1 1 1 1 1 1 1 1 > > etc... > > > > I wish to calculate the sum of each column for certain > number of rows. For example if I want sum of the data after > each 3 rows, it should display > > 1 0 1 1 1 1 1 1 > > 1 1 1 1 0 0 1 1 > > 2 3 2 3 3 2 3 2 > > > > So far, this is what I have done > > xx<-read.table("data.csv",header=FALSE) > > ss<-t(apply(xx,2,sum)) # which displayed the sum of > all rows > > > > I tried my best to look for solution on the Internet > but so far haven't managed to find it. I am extremely > grateful if someone can point me how to go about it. > Thanks. > > > > Kelvin > > > > ______________________________________________ > > R-help@r-project.org > mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > > and provide commented, minimal, self-contained, > reproducible code. > > > > -- Dimitris Rizopoulos > Assistant Professor > Department of Biostatistics > Erasmus University Medical Center > > Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands > Tel: +31/(0)10/7043478 > Fax: +31/(0)10/7043014 > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.