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Posted to jira@arrow.apache.org by "Dragoș Moldovan-Grünfeld (Jira)" <ji...@apache.org> on 2022/03/10 14:54:00 UTC

[jira] [Created] (ARROW-15904) [C++] Support rolling backwards and forwards with temporal arithmetic

Dragoș Moldovan-Grünfeld created ARROW-15904:
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             Summary: [C++] Support rolling backwards and forwards with temporal arithmetic
                 Key: ARROW-15904
                 URL: https://issues.apache.org/jira/browse/ARROW-15904
             Project: Apache Arrow
          Issue Type: New Feature
          Components: C++
            Reporter: Dragoș Moldovan-Grünfeld


Original description in ARROW-11090: 
"This should also cover the ability to do with and without rollback (so have the ability to do e.g. 2021-03-30 minus 1 month and either get a null back, or 2021-02-28), plus the ability to specify whether to rollback to the first or last, and whether to preserve or rest the time.)"

For example, in R, lubridate has the following functionality:

* {{rollbackward()}} or {{rollback()}} which changes a date to the last day of the previous month or to the first day of the current month
* {{rollforward()}} which rolls to the last day of the current month or to the first day of the next month.
* all of the above also offer the option to preserve hms (hours, minutes and seconds) when rolling. 

This functionality underpins functions such as {{%m-%}} and {{%m+%}} which are used to add or subtract months to a date without exceeding the last day of the new month.

{code:r}
library(lubridate)

jan <- ymd_hms("2010-01-31 03:04:05")
jan + months(1:3) # Feb 31 and April 31 returned as NA
#> [1] NA                        "2010-03-31 03:04:05 UTC"
#> [3] NA
# NA "2010-03-31 03:04:05 UTC" NA
jan %m+% months(1:3) # No rollover
#> [1] "2010-02-28 03:04:05 UTC" "2010-03-31 03:04:05 UTC"
#> [3] "2010-04-30 03:04:05 UTC"

leap <- ymd("2012-02-29")
"2012-02-29 UTC"
#> [1] "2012-02-29 UTC"
leap %m+% years(1)
#> [1] "2013-02-28"
leap %m+% years(-1)
#> [1] "2011-02-28"
leap %m-% years(1)
#> [1] "2011-02-28"

x <- ymd_hms("2019-01-29 01:02:03")
add_with_rollback(x, months(1))
#> [1] "2019-02-28 01:02:03 UTC"
add_with_rollback(x, months(1), preserve_hms = FALSE)
#> [1] "2019-02-28 UTC"
add_with_rollback(x, months(1), roll_to_first = TRUE)
#> [1] "2019-03-01 01:02:03 UTC"
add_with_rollback(x, months(1), roll_to_first = TRUE, preserve_hms = FALSE)
#> [1] "2019-03-01 UTC"
{code}



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