The R Book

Finding Closest Values

Finding the value in a vector that is closest to a specified value is straightforward using which. Here, we want to find the value of xv that is closest to 108.0:

which(abs(xv-108)==min(abs(xv-108)))

[1]  332

The closest value to 108.0 is in location 332. But just how close to 108.0 is this 332nd value? We use 332 as a subscript on xv to find this out

xv[332]

[1]  108.0076

Thus, we can write a function to return the closest value to a specified value (sv)

closest<-function(xv,sv){
xv[which(abs(xv-sv)==min(abs(xv-sv)))] }

and run it like this:

closest(xv,108)

[1] 108.0076