Implement as_date

See tidyverse#355

R/coercion.r

@@ -548,3 +548,28 @@ setMethod("as.character", signature(x = "Duration"), function(x, ...){
 setMethod("as.character", signature(x = "Interval"), function(x, ...){
   format(x)
 })
+
+
+
+#' Coerce to a Date
+#'
+#' @param x a POSIXct, POSIXt date
+#'
+#' @return a \code{\link{Date}} object that corresponds to the day of the year
+#' in the time zone of \code{x}.
+#' @export
+#'
+#' @examples
+#' dt1 <- as.POSIXct("2010-08-03 00:59:59.23")
+#' as_date(dt1)
+#' dt2 <- as.POSIXct("2010-08-03 00:59:59.23", tz="Europe/London")
+#' as_date(dt2)
+setGeneric(name = "as_date", def = function(x) standardGeneric("as_date"))
+
+#' @export
+setMethod(f = "as_date", signature = "POSIXt", definition = function (x) {
+  as.Date(x, tz(x))
+})
+
+
+