in_interval: Determine if Value Lies within Interval
In Kmisc: Kevin Miscellaneous

This function determines whether elements of a numeric vector x lie within boundaries [lo, hi). Marginally slower than the R equivalent code x >= lo & x < hi for small vectors; much faster for very large vectors.

1	in_interval(x, lo, hi, include.lower = TRUE, include.upper = FALSE)

`x`	numeric. vector of numbers.
`lo`	numeric, length 1. lower boundary.
`hi`	numeric, length 1. upper boundary.
`include.lower`	boolean. include the lower endpoint?
`include.upper`	boolean. include the upper endpoint?

x <- runif(100); lo <- 0.5; hi <- 1
f <- function(x, lo, hi) {
  return( x >= lo & x < hi )
}
stopifnot( all( in_interval( x, lo, hi ) == f(x, lo, hi) ) )