[R] Help with which()

[naw3 at duke.edu]

Hi,

I'm using which to find the position of a value in my data table, and it is
returning the correct position and the position of another number that differs
by an extra decimal place. For example, when I do:

where1<-which(Operons==3573.1,arr.ind=TRUE)

it returns the position of that number and of 3573.15.

Is it possible to get the function to only return a position if the number
matches exactly?

Thanks,
-Nina