dragosmg commented on a change in pull request #12506:
URL: https://github.com/apache/arrow/pull/12506#discussion_r833113113
##########
File path: r/R/dplyr-funcs-datetime.R
##########
@@ -189,6 +189,65 @@ register_bindings_datetime <- function() {
})
}
+register_bindings_duration <- function() {
+ register_binding("difftime", function(time1,
+ time2,
+ tz,
+ units = c("auto", "secs", "mins",
+ "hours", "days", "weeks")) {
+ units <- match.arg(units)
+ if (units != "secs") {
+ abort("`difftime()` with units other than seconds not supported in
Arrow")
+ }
+
+ if (!missing(tz)) {
+ warn("`tz` is an optional argument to `difftime()` in R and will not be
used in Arrow")
+ }
+
+ time1 <- build_expr("cast", time1, options = cast_options(to_type =
timestamp()))
+ time2 <- build_expr("cast", time2, options = cast_options(to_type =
timestamp()))
+
+ build_expr("cast", time1 - time2, options = cast_options(to_type =
duration("s")))
+ })
+
+ register_binding("as.difftime", function(x,
+ format = "%X",
+ units = "auto") {
+ # windows doesn't seem to like "%X"
+ if (format == "%X" & tolower(Sys.info()[["sysname"]]) == "windows") {
+ format <- "%H:%M:%S"
+ }
+
+ if (units != "secs") {
+ abort("`as.difftime()` with units other than seconds not supported in
Arrow")
+ }
+
+ if (call_binding("is.character", x)) {
+ x <- build_expr("strptime", x, options = list(format = format, unit =
0L))
+ y <- build_expr("strptime", "0:0:0", options = list(format = "%H:%M:%S",
unit = 0L))
+ diff_x_y <- call_binding("difftime", x, y, units = "secs")
+ return(diff_x_y)
+ }
Review comment:
I've done a bit more thinking and digging around this. It turns out
{arrow} maps `time32()` to R's `difftime`. So, in theory, we don't need `y` and
we could simply cast `x` to `time32()`. In practice it's not as straightforward
since `x` is both `hms` and `difftime`:
``` r
library(arrow, warn.conflicts = FALSE)
library(dplyr, warn.conflicts = FALSE)
library(lubridate, warn.conflicts = FALSE)
test_df <- tibble(
hms_string = c("0:7:45", "12:34:56"),
hm_string = c("7:45", "12:34"),
int = c(30L, 75L),
integerish_dbl = c(31, 76),
dbl = c(31.2, 76.4)
)
test_df %>%
mutate(hms_difftime = as.difftime(hms_string, units = "secs"))
#> # A tibble: 2 × 6
#> hms_string hm_string int integerish_dbl dbl hms_difftime
#> <chr> <chr> <int> <dbl> <dbl> <drtn>
#> 1 0:7:45 7:45 30 31 31.2 465 secs
#> 2 12:34:56 12:34 75 76 76.4 45296 secs
test_df %>%
arrow_table() %>%
mutate(hms_difftime = as.difftime(hms_string, units = "secs")) %>%
collect()
#> # A tibble: 2 × 6
#> hms_string hm_string int integerish_dbl dbl hms_difftime
#> <chr> <chr> <int> <dbl> <dbl> <drtn>
#> 1 0:7:45 7:45 30 31 31.2 465 secs
#> 2 12:34:56 12:34 75 76 76.4 45296 secs
compare_dplyr_binding(
.input %>%
mutate(hms_difftime = as.difftime(hms_string, units = "secs")) %>%
collect(),
test_df
)
#> Error: `object` (`actual`) not equal to `expected` (`expected`).
#>
#> `class(actual$hms_difftime)`: "hms" "difftime"
#> `class(expected$hms_difftime)`: "difftime"
```
<sup>Created on 2022-03-23 by the [reprex
package](https://reprex.tidyverse.org) (v2.0.1)</sup>
We could simply ignore attributes but that doesn't feel right.
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