> But you got only two (eventually one) distinct values, right? Look at > the code for 'ifelse': yes and no are only called once each, then > recycled to desired length. > > I guess you want something like > > x <- rnorm(10) > y <- rnorm(10) > z <- rnorm(10) > y1 <- ifelse(x > 0, y, z) > Thanks for the help.
Although this would do the trick, is there a way to call repetitively rnorm (rpois...) *inside the ifelse* rather than constructing the vector outside ? Like in the following where cos() and sin() functions are evaluated for each row : x <- rnorm(10) y1 <- ifelse(x > 0, cos(x), sin(x)) I am trying to understand the difference of behaviour. R acts as if rnorm(1) return value were known after the first call and does not evaluate rnorm(1) in y1 <- ifelse(x > 0, rnorm(1) , rnorm(1)) again after the first evaluation. Jacques. ______________________________________________ R-help@stat.math.ethz.ch 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.
