R: NaNs produced

Question

I have a time series in R Studio. Now I want to calculate the log() of this series. I tried the following:

i <- (x-y) 
ii <- log(i)

But

Answer 1

As I said in my comment, to know which observation generated the NaN, you can use function which:

i <- c(9,8,4,5,7,1,6,-1,8,4)
which(is.nan(log(i))) # 8