Hi, TRy this: set.seed(52) dat1<- as.data.frame(matrix(sample(1:40,100*60,replace=TRUE), nrow=600))
lapply(split(dat1,((seq_len(nrow(dat1))-1)%/% 60)+1),nrow) #$`1` #[1] 60 #$`2` #[1] 60 #$`3` #[1] 60 res<-lapply(split(dat1,((seq_len(nrow(dat1))-1)%/% 60)+1),colMeans) res[1:2] #$`1` # V1 V2 V3 V4 V5 V6 V7 V8 #20.95000 20.53333 20.55000 21.13333 20.10000 18.33333 21.13333 20.50000 # V9 V10 #20.86667 18.70000 #$`2` # V1 V2 V3 V4 V5 V6 V7 V8 #22.16667 19.85000 19.73333 22.26667 18.80000 19.93333 18.85000 20.46667 # V9 V10 #17.81667 18.51667 A.K. ----- Original Message ----- From: Ye Lin <ye...@lbl.gov> To: r-help@r-project.org Cc: Sent: Wednesday, April 10, 2013 1:46 PM Subject: [R] how to calculate average of each column Hey All, I have a large dataset and I want to calculate the average of each column then return a new dataset. Here is my question: I dont know if there is a function that can allow me to calculate the average every 60 records of data in the whole dataset, and return a new data frame. Not sure if I have to divide the dataset first for every 60, then do the mean or can i directly do that. thanks for your help! cici [[alternative HTML version deleted]] ______________________________________________ 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. ______________________________________________ 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.
