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https://issues.apache.org/jira/browse/ARROW-16596?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17538219#comment-17538219
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Dragoș Moldovan-Grünfeld edited comment on ARROW-16596 at 5/17/22 1:53 PM:
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I think we would need to if we wanted to emulate the behaviour. I think it
refers to the fact that other parsing functions in lubridate use the parsing
functionality native to R (e.g. R's {{strptime}} as opposed to lubridate's
{{{}fast_strptime){}}}.
was (Author: dragosmg):
I think we would need to if we wanted to emulate the behaviour. I think it
refers to the fact that other parsing functions in lubridate use the parsing
functionality native to R (e.g. R's {{strptime}} as opposed to lubridate's
{{{}fast_strptime{}}}.
> [C++] Add a strptime option to control the cutoff between 1900 and 2000 when
> %y
> --------------------------------------------------------------------------------
>
> Key: ARROW-16596
> URL: https://issues.apache.org/jira/browse/ARROW-16596
> Project: Apache Arrow
> Issue Type: Sub-task
> Components: C++, R
> Affects Versions: 8.0.0
> Reporter: Dragoș Moldovan-Grünfeld
> Priority: Major
>
> When parsing to datetime a string with year in the short format ({{{}%y{}}}),
> it would be great if we could have control over the cutoff point between 1900
> and 2000. Currently it is implicitly set to 68:
> {code:r}
> library(arrow, warn.conflicts = FALSE)
> a <- Array$create(c("68-05-17", "69-05-17"))
> call_function("strptime", a, options = list(format = "%y-%m-%d", unit = 0L))
> #> Array
> #> <timestamp[s]>
> #> [
> #> 2068-05-17 00:00:00,
> #> 1969-05-17 00:00:00
> #> ]
> {code}
> For example, lubridate named this argument {{cutoff_2000}} argument (e.g. for
> {{{}fast_strptime){}}}. This works as follows:
> {code:r}
> library(lubridate, warn.conflicts = FALSE)
> dates_vector <- c("68-05-17", "69-05-17", "55-05-17")
> fast_strptime(dates_vector, format = "%y-%m-%d")
> #> [1] "2068-05-17 UTC" "1969-05-17 UTC" "2055-05-17 UTC"
> fast_strptime(dates_vector, format = "%y-%m-%d", cutoff_2000 = 50)
> #> [1] "1968-05-17 UTC" "1969-05-17 UTC" "1955-05-17 UTC"
> fast_strptime(dates_vector, format = "%y-%m-%d", cutoff_2000 = 70)
> #> [1] "2068-05-17 UTC" "2069-05-17 UTC" "2055-05-17 UTC"
> {code}
> In the {{lubridate::fast_strptime()}} documentation it is described as
> follows:
> {quote}cutoff_2000
> integer. For y format, two-digit numbers smaller or equal to cutoff_2000 are
> parsed as though starting with 20, otherwise parsed as though starting with
> 19. Available only for functions relying on lubridates internal parser.
> {quote}
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