Hi, Try: set.seed(45) mat1 <- matrix(rnorm(500), ncol=1) n <- dim(mat1)[1] indx <- as.numeric(gl(n,100,n)) tapply(mat1[,1], indx, FUN= mean, na.rm=TRUE) # 1 2 3 4 5 # 0.08118335 -0.05222418 -0.20042223 -0.03530833 -0.06093053
If you have more than one column: set.seed(49) dat1 <- as.data.frame(matrix(rnorm(1000), ncol=2)) library(plyr) ddply(dat1,.(indx), numcolwise(mean, na.rm=TRUE)) A.K. On Thursday, June 12, 2014 8:11 AM, Pat-74100 <leonardsqual...@hotmail.com> wrote: Hi @Rolf Turner: So you're wrong, I can guaranty you this is not homework ... but just for a graph I'm trying do plot. @Arun: Yes I've done a mistake, it is 1-100 , 101-200 etc .. or even 1-50,51-100 etc. The range is not important. Thanks > Date: Thu, 12 Jun 2014 02:04:26 -0700 > From: smartpink...@yahoo.com > Subject: Re: [R] Average value in a particular range of a matrix > To: leonardsqual...@hotmail.com > > Hi Pat, > Is it 1-100, 101-200, 201-300,.. or just the way you described? > A.K. > > > > > On Wednesday, June 11, 2014 11:45 PM, Pat-74100 <leonardsqual...@hotmail.com> > wrote: > Hi > > I have a matrix with values of size 1*500 i have to find the avg > value of first 1 to 100 ,avg value of 100 - 200 and so on up to 400-500. > is there any function to find the average of 1 -100 and 100 - 200, 200 - > 300,300 - 400,400 - 500 ?? > > Thanks > > [[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.
