[ARROW-16316] [R] How to round the timestamps in a mutate statement?

• Type: Wish
• Status: Closed
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 7.0.0
• Component/s: R
• External issue URL: https://github.com/apache/arrow/issues/31702
• Assignee: Unassigned
• Reporter: Zsolt Kegyes-Brassai
• Created: 25/Apr/22 12:19
• Updated: 11/Jan/23 11:43
• Resolved: 06/Jul/22 14:25

Description

I was trying to aggregate over time using different granularity. Usually I would use the lubridate::floor_date() , which is currently not supported for parquet datasets.

Is there any comprehensive list of supported list of currently supported lubridate (or dplyr) verbs? Maybe, it’s only my fault, but except the changelog I haven’t find any relevant information.

 

Later I found that the round_temporal() function is exposed to R. 
But I am struggling to find the right syntax inside a mutate statement to apply on a timestamp[us, tz=UTC] type column.

new_dataset |>
  mutate(time = arrow_round_temporal(time))
#>  Error: Invalid: Attempted to initialize KernelState from null FunctionOptions

 

Here are some other attempts:

library(arrow)

arrow_now <- Scalar$create(lubridate::now())
(arrow_now)
#> Scalar
#> 2022-04-25 11:44:33.805609
call_function("round_temporal", arrow_now)
#> Scalar
#> 2022-04-25 00:00:00.000000
call_function("round_temporal", arrow_now, unit = "day")
#> Error: Argument 2 is of class character but it must be one of "Array", "ChunkedArray", "RecordBatch", "Table", or "Scalar"
arrow_unit <- Scalar$create("day")
(arrow_unit)
#> Scalar
#> day
call_function("round_temporal", arrow_now, unit = arrow_unit)
#> Error: Invalid: Function 'round_temporal' accepts 1 arguments but attempted to look up kernel(s) with 2

 

Issue Links

• duplicates: ARROW-14821 [R] Implement bindings for lubridate's floor_date, ceiling_date, and round_date
• is related to: ARROW-14821 [R] Implement bindings for lubridate's floor_date, ceiling_date, and round_date
• relates to: ARROW-16319 [R] [Docs] Document the lubridate functions we support in {arrow}