if else in R
On Nov 19, 2013, at 5:30 PM, Gary Dong wrote:
Dear R users,
I am a R beginner and I am having trouble in using "If Else" in R. Here is
an example:
## create a data frame
a<-c(1,2,3,4)
b<-c(2,0,5,0)
ab<-data.frame(cbind(a,b))
##calculate c, which is the ratio between a and b
if(ab$b>0) {
ab$c<-ab$a/ab$b
} else {
ab$c<-0
}
here is the error I got:
Consider this alternative: ab$c <- (ab >0 ) * ab$a/ab$b Although in general, you will probably use `ifelse`. ?ifelse # different than ?"if"
David Winsemius Alameda, CA, USA