paleolimbot commented on a change in pull request #12324:
URL: https://github.com/apache/arrow/pull/12324#discussion_r806877934
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File path: r/R/array.R
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@@ -216,6 +216,76 @@ Array$create <- function(x, type = NULL) {
#' @include arrowExports.R
Array$import_from_c <- ImportArray
+
+#' Concatenate zero or more Arrays
+#'
+#' @param ... zero or more [Array] objects to concatenate
+#' @param type An optional `type` describing the desired
+#' type for the final Array.
+#'
+#' @return An [Array]
+#' @export
+#'
+#' @examples
+#' concat_arrays(Array$create(1:3), Array$create(4:5))
+#'
+concat_arrays <- function(..., type = NULL) {
+ dots <- lapply(list2(...), Array$create, type = type)
+
+ if (length(dots) == 0 && is.null(type)) {
+ return(Array$create(logical(), type = null()))
+ } else if (length(dots) == 0) {
+ return(Array$create(logical(), type = null())$cast(type))
+ }
+
+ if (!is.null(type)) {
+ dots <- lapply(dots, function(array) array$cast(type))
+ }
+
+ arrow__Concatenate(dots)
+}
+
+# The c() method uses non-standard dispatch in R
+# and has some peculiarities when multiple types are passed to ....
+# However, with a method defined for all subclasses of Array, it will
+# do what a user expects most of the time.
Review comment:
As @wjones127 noted above, if we *don't* define it we get even weirder
behaviour. I think it's more intuitive to define it than omit but am happy to
leave it out too. The upside is that it's the first thing an R user might think
to do (as Will thought to do immediately based on the comment above).
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