<AsIs> methods for rescale() (#404)

NAMESPACE

@@ -12,6 +12,7 @@ S3method(offset_by,numeric)
 S3method(plot,trans)
 S3method(print,trans)
 S3method(rescale,"NULL")
+S3method(rescale,AsIs)
 S3method(rescale,Date)
 S3method(rescale,POSIXt)
 S3method(rescale,difftime)
@@ -20,6 +21,7 @@ S3method(rescale,integer64)
 S3method(rescale,logical)
 S3method(rescale,numeric)
 S3method(rescale_mid,"NULL")
+S3method(rescale_mid,AsIs)
 S3method(rescale_mid,Date)
 S3method(rescale_mid,POSIXt)
 S3method(rescale_mid,dist)

NEWS.md

@@ -8,6 +8,8 @@
   vectors during training. Mixing of character and factor data will still lead
   to different results depending on the training order.
 * Add a rescale method for `difftime` objects (#382)
+* `rescale(I(x), ...)` and `rescale_mid(I(x), ...)` return `I(x)` unaltered 
+  (@teunbrand, #403).
 * The `scale_cut` argument in `number()` now works as advertised for values 
   below the lowest cut value (#346)
 * `label_dollar()` has been superseeded by `label_currency()` for clarity (#344)

R/bounds.R

@@ -5,6 +5,9 @@
 #' @param from input range (vector of length two).  If not given, is
 #'   calculated from the range of `x`
 #' @param ... other arguments passed on to methods
+#' @details
+#' Objects of class `<AsIs>` are returned unaltered.
+#'
 #' @keywords manip
 #' @export
 #' @examples
@@ -62,6 +65,9 @@ rescale.integer64 <- function(x, to = c(0, 1), from = range(x, na.rm = TRUE), ..
 #' @export
 rescale.difftime <- rescale.numeric
 
+#' @rdname rescale
+#' @export
+rescale.AsIs <- function(x, to, from, ...) x
 
 #' Rescale vector to have specified minimum, midpoint, and maximum
 #'
@@ -72,6 +78,8 @@ rescale.difftime <- rescale.numeric
 #'   calculated from the range of `x`
 #' @param mid mid-point of input range
 #' @param ... other arguments passed on to methods
+#' @details
+#' Objects of class `<AsIs>` are returned unaltered.
 #' @examples
 #' rescale_mid(1:100, mid = 50.5)
 #' rescale_mid(runif(50), mid = 0.5)
@@ -133,6 +141,10 @@ rescale_mid.integer64 <- function(x, to = c(0, 1), from = range(x, na.rm = TRUE)
 }
 
 
+#' @rdname rescale_mid
+#' @export
+rescale_mid.AsIs <- function(x, to, from, ...) x
+
 #' Rescale numeric vector to have specified maximum
 #'
 #' @export

tests/testthat/test-bounds.R

@@ -71,6 +71,11 @@ test_that("scaling is possible with NULL values", {
   expect_null(rescale_mid(NULL))
 })
 
+test_that("rescaling does not alter AsIs objects", {
+  expect_identical(I(1:3), rescale(I(1:3), from = c(0, 4)))
+  expect_identical(I(1:3), rescale_mid(I(1:3), from = c(0, 4), mid = 1))
+})
+
 test_that("scaling is possible with logical values", {
   expect_equal(rescale(c(FALSE, TRUE)), c(0, 1))
   expect_equal(rescale_mid(c(FALSE, TRUE), mid = 0.5), c(0, 1))