Hi, matrix has a 2 dimensions.
Is this work: a<-matrix(rep(c(1,2),c(5,5)),ncol=1) dim(a) for (i in 1:10) { ifelse(a[i,]==1, a[i,]<-runif(1,3,4.5), a[i,]) } a Andrija On Tue, Mar 8, 2011 at 1:07 PM, dpender <d.pende...@research.gla.ac.uk>wrote: > Hi, > > I am having some problems using the if statement correctly. I have used it > many times previously so I dona't know what is different with this case. > Here is my problem: > > I have a 1X10 matrix of values as follows: > > > H.MC <http://h.mc/> > [,1] > [1,] 4.257669 > [2,] 7.023242 > [3,] 4.949857 > [4,] 5.107000 > [5,] 4.257669 > [6,] 4.257669 > [7,] 4.257669 > [8,] 4.257669 > [9,] 4.257669 > [10,] 4.257669 > > What I want to do is replace all the values if 4.257669 with a random > number > between 3 and 4.5. To do this I have: > > H.MC.fin <- matrix(0,10,1) > > for (j in 1:10) { > > if(H.MC <http://h.mc/>[j] == 4.257669) H.MC.fin[j] <-runif(1,3,4.5) else > H.MC.fin[j] <- > H.MC <http://h.mc/>[j] > > } > > This doesn't seem to do anything and H.MC.fin is the same as > H.MC<http://h.mc/> > . > > Does anyone know what I am doing wrong? > > Thanks, > > Doug > > > -- > View this message in context: > http://r.789695.n4.nabble.com/If-Statement-tp3341167p3341167.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > [[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.