between is vectorised. closes Rdatatable#534.

R/between.R

@@ -1,9 +1,9 @@
 
-between <- function(x,lower,upper,incbounds=TRUE)
-{
+between <- function(x,lower,upper,incbounds=TRUE) {
  if(incbounds) x>=lower & x<=upper
  else x>lower & x<upper
 }
 
-"%between%" <- function(x,y) between(x,y[1],y[2],incbounds=TRUE)
+# %between% is vectorised, #534.
+"%between%" <- function(x,y) between(x,y[[1]],y[[2]],incbounds=TRUE)
 # If we want non inclusive bounds with %between%, just +1 to the left, and -1 to the right (assuming integers)

README.md

@@ -82,6 +82,8 @@
 
  32. Non-equi joins are now possible using the familiar `on=` syntax. With this, the set of binary operators extend from just `==` to `>=`, `>`, `<=`, `<` and `==`. For e.g., `X[Y, on=.(a, b>b)]` looks for `X.a == Y.a` first and within those matching rows for rows where`X.b > Y.b`. Partly addreses [#1452](https://github.com/Rdatatable/data.table/issues/1452).
 
+ 33. `%between%` is vectorised which means we can now do: `DT[x %between% list(y,z)]` which is equivalent to `DT[x >= y & x <= z]`, [#534](https://github.com/Rdatatable/data.table/issues/534). Thanks @MicheleCarriero for filing the issue and the idea.
+
 #### BUG FIXES
 
  1. Now compiles and runs on IBM AIX gcc. Thanks to Vinh Nguyen for investigation and testing, [#1351](https://github.com/Rdatatable/data.table/issues/1351).

man/between.Rd

@@ -3,17 +3,17 @@
 \alias{\%between\%}
 \title{ Convenience function for range subset logic. }
 \description{
- Intended for use in \code{i} in \code{[.data.table}.
+ Intended for use in \code{i} in \code{[.data.table}. From \code{v1.9.8}, \code{between} is vectorised. 
 }
 \usage{
 between(x,lower,upper,incbounds=TRUE)
 x \%between\% y
 }
 \arguments{
  \item{x}{ Any orderable vector, i.e., those with relevant methods for \code{`<=`}, such as \code{numeric}, \code{character}, \code{Date}, ... }
- \item{lower}{ Lower range bound. }
- \item{upper}{ Upper range bound. }
- \item{y}{ A length-2 vector, with \code{y[1]} interpreted as \code{lower} and \code{y[2]} as \code{upper}. }
+ \item{lower}{ Lower range bound. Usually of length=\code{1} or \code{length(x)}.}
+ \item{upper}{ Upper range bound. Usually of same length as \code{lower}.}
+ \item{y}{ A length-2 \code{vector} or \code{list}, with \code{y[[1]]} interpreted as \code{lower} and \code{y[[2]]} as \code{upper}.} 
  \item{incbounds}{ \code{TRUE} means inclusive bounds, i.e., [lower,upper]. \code{FALSE} means exclusive bounds, i.e., (lower,upper). }
 }
 % \details{
@@ -24,7 +24,9 @@ x \%between\% y
 \note{ Current implementation does not make use of ordered keys. \code{incbounds} is set to \code{TRUE} for the infix notation \code{\%between\%}. }
 \seealso{ \code{\link{data.table}}, \code{\link{like}} }
 \examples{
-DT = data.table(a=1:5, b=6:10)
-DT[b \%between\% c(7,9)]
+DT = data.table(x=1:5, y=6:10, z=c(5:1))
+DT[y \%between\% c(7,9)]
+# NEW feature in v1.9.8, vectorised between
+DT[z \%between\% list(x,y)]
 }
 \keyword{ data }