Re: [R] (newbie) sum for certain number of rows

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 wrote: > From: Dimitris Rizopoulos > Subject: Re: [R] (newbie) sum for certain number of rows > To: "kelvin lau&q

Re: [R] (newbie) sum for certain number of rows

In the zoo package, rollapply can do that. > library(zoo) > out <- rollapply(ts(dat), width = 3, by = 3, sum) > out Time Series: Start = 3 End = 9 Frequency = 0.333 V1 V2 V3 V4 V5 V6 V7 V8 3 1 0 1 1 1 1 1 1 6 1 1 1 1 0 0 1 1 9 2 3 2 3 3 2 3 2 This gives a "ts

Re: [R] (newbie) sum for certain number of rows

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)