[C++] Provide a way to go from numeric to duration #31298
Description
Update: I keep forgetting that R integers are translated into int32 (since R does not have int64). int64 -> duration is supported.
Would it make sense to support float -> duration or int32 -> duration?
======================
Currently it is not possible to directly create a duration object from a numeric one (for example through casting).
library(arrow)
a <- Array$create(32L)
a$cast(duration("s"))
#> Error: NotImplemented: Unsupported cast from int32 to duration using function cast_duration
#> /Users/dragos/Documents/arrow/cpp/src/arrow/compute/function.cc:231 DispatchBest(&inputs)This underpins a lot of the date-time arithmetic in R, which support the conversion/ coercion of an integer to difftime (R's equivalent for duration), such as in the pipeline below.
library(arrow, warn.conflicts = FALSE)
#> See arrow_info() for available features
library(dplyr, warn.conflicts = FALSE)
library(lubridate, warn.conflicts = FALSE)
df <- tibble(time = as_datetime(c("2022-03-07 15:00:28", "2022-03-06 14:00:28")))
df
#> # A tibble: 2 × 1
#> time
#> <dttm>
#> 1 2022-03-07 15:00:28
#> 2 2022-03-06 14:00:28
df %>%
mutate(time2 = time + seconds(2))
#> # A tibble: 2 × 2
#> time time2
#> <dttm> <dttm>
#> 1 2022-03-07 15:00:28 2022-03-07 15:00:30
#> 2 2022-03-06 14:00:28 2022-03-06 14:00:30Reporter: Dragoș Moldovan-Grünfeld / @dragosmg
Related issues:
- [C++] Cast to duration from types other than int64 (is duplicated by)
- [R] Helper function for casting from float to duration via int64() (relates to)
- [C++][R] Can't cast integer difftime to duration (but works with double) (supercedes)
Note: This issue was originally created as ARROW-15862. Please see the migration documentation for further details.