How can I create an infix

Question

I would like to have an infix operator %between% in R -- to check to see if x is between lower bound l and upper bound

Answer 1

This function exists in the package data.table (with the slight difference that the bounds are included), implemented as:

between <- function(x,lower,upper,incbounds=TRUE)
{
  if(incbounds) x>=lower & x<=upper
  else x>lower & x

It can be used as between(x,lower,upper) or x %between% c(lower, upper)