dragosmg commented on a change in pull request #12433:
URL: https://github.com/apache/arrow/pull/12433#discussion_r816625715
##########
File path: r/R/dplyr-funcs-type.R
##########
@@ -76,6 +76,64 @@ register_bindings_type_cast <- function() {
register_binding("as.numeric", function(x) {
Expression$create("cast", x, options = cast_options(to_type = float64()))
})
+ register_binding("as.Date", function(x,
+ format = NULL,
+ tryFormats = "%Y-%m-%d",
+ origin = "1970-01-01",
+ tz = "UTC") {
+
+ if (call_binding("is.Date", x)) {
+ # base::as.Date() first converts to the desired timezone and then
extracts
+ # the date, which is why we need to go through timestamp() first
+ return(x)
+
+ # cast from POSIXct
+ } else if (call_binding("is.POSIXct", x)) {
+ if (tz == "UTC") {
+ interim_x <- build_expr("cast", x, options = cast_options(to_type =
timestamp(timezone = tz)))
+ } else {
+ abort("`as.Date()` with a timezone different to 'UTC' is not supported
in Arrow")
+ }
+
+ # cast from character
+ } else if (call_binding("is.character", x)) {
+ # this could be improved with tryFormats once strptime returns NA and we
+ # can use coalesce - https://issues.apache.org/jira/browse/ARROW-15659
+ # TODO revisit once https://issues.apache.org/jira/browse/ARROW-15659 is
done
+ if (is.null(format)) {
+ if (length(tryFormats) == 1) {
+ format <- tryFormats[1]
+ } else {
+ abort("`as.Date()` with multiple `tryFormats` is not supported in
Arrow yet")
+ }
+ }
+ # if x is not an expression (e.g. passed as filter), convert it to one
+ if (!inherits(x, "Expression")) {
+ x <- build_expr("cast", x, options = cast_options(to_type = type(x)))
+ }
Review comment:
I introduced that step (converting a character `x` to `Expression`) as a
way of dealing with the errors we were seeing with `filter()`. In
`filter.arrow_dplyr_query()` we get the following error after tidy-eval-ing the
filter expression:
```r
> filters <- lapply(filts, arrow_eval, arrow_mask(.data))
> filters
[[1]]
[1] "Expression arguments must be Expression objects"
attr(,"class")
[1] "try-error"
attr(,"condition")
<assertError: Expression arguments must be Expression objects>
```
where `filts` is:
```r
> filts
<list_of<quosure>>
[[1]]
<quosure>
expr: ^ts >= as.Date("2015-05-04")
env: 0x297eaa768
```
and the original test is:
```r
# ds is an open dataset
ds %>%
filter(ts >= as.Date("2015-05-04")) %>%
filter(part == 1) %>%
select(ts) %>%
collect()
```
As far as I understand it, it fails due to `"2015-05-04"` being a character
and not an `Expression` object. Inside the `filter. ...` method:
```r
> b <- arrow_eval(filts[[1]], arrow_mask(.data))
> b
[1] "Expression arguments must be Expression objects"
attr(,"class")
[1] "try-error"
attr(,"condition")
<assertError: Expression arguments must be Expression objects>
```
Hence my approach: if we somehow get to that point in the function body and,
for some reason, character `x` is not yet an `Expression, make it into one.
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