Re: [R] Unexpected date format coercion
On Thu, 01 Jul 2021, Jeremie Juste writes:
> Hello
>
> On Thursday, 1 Jul 2021 at 08:25, PIKAL Petr wrote:
>> Hm.
>>
>> Seems to me, that both your codes are wrong but printing in Linux is
>> different from Windows.
>>
>> With
>> as.Date("20-12-2020","%Y-%m-%d")
>> you say that 20 is year (actually year 20) and 2020 is day and only first
>> two values are taken (but with some valueas result is NA)
>>
>> I can confirm 4.0.3 in Windows behaves this way too.
>>> as.Date("20-12-2020","%Y-%m-%d")
>> [1] "0020-12-20"
>
> Many thanks for confirming this.
>
>
> On Thursday, 1 Jul 2021 at 18:22, Jim Lemon wrote:
>> Hi Jeremie,
>> Try:
>>
>> as.Date("20-12-2020","%y-%m-%d")
>> [1] "2020-12-20"
>
> Thanks for this info. I'm looking for something that produce NA if the
> date is not exactly in the specified format so that it can be
> corrected. I was relying on the format parameter of the date for that.
>
> The issue is that there can be so many variations in date format that for the
> time
> being I still find it easier to delegate the correction to the user. A
> particular nasty case is when there are multiple date format in the same
> column.
>
>
> Best regards,
> Jeremie
>
You could explicitly test whether the specified format
is as expcected, perhaps with a regex such as
s <- c("2020-01-20", "20-12-2020")
grepl("^[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]$", s)
and/or by checking the components of the dates:
valid_Date <- function(s) {
tmp <- strsplit(s, "[-]")
year <- as.numeric(sapply(tmp, `[[`, 1))
valid.year <- year < 2500 & year > 1800
month <- as.numeric(sapply(tmp, `[[`, 2))
valid.month <- month >= 0 & month <= 12
day <- as.numeric(sapply(tmp, `[[`, 3))
valid.day <- day >= 1 & day <= 31
ans <- as.Date(s)
ans[!(valid.year & valid.month & valid.day)] <- NA
ans
}
--
Enrico Schumann
Lucerne, Switzerland
http://enricoschumann.net
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Re: [R] Unexpected date format coercion
Hi
Maybe you could inspect
parse_date_time {lubridate} R Documentation
from package lubridate.
Or see answers here
https://stackoverflow.com/questions/25463523/how-to-convert-variable-with-mixed-date-formats-to-one-format
Cheers
Petr
> -Original Message-
> From: Jeremie Juste
> Sent: Thursday, July 1, 2021 11:00 AM
> To: PIKAL Petr
> Cc: r-help
> Subject: Re: [R] Unexpected date format coercion
>
> Hello
>
> On Thursday, 1 Jul 2021 at 08:25, PIKAL Petr wrote:
> > Hm.
> >
> > Seems to me, that both your codes are wrong but printing in Linux is
> > different from Windows.
> >
> > With
> > as.Date("20-12-2020","%Y-%m-%d")
> > you say that 20 is year (actually year 20) and 2020 is day and only
> > first two values are taken (but with some valueas result is NA)
> >
> > I can confirm 4.0.3 in Windows behaves this way too.
> >> as.Date("20-12-2020","%Y-%m-%d")
> > [1] "0020-12-20"
>
> Many thanks for confirming this.
>
>
> On Thursday, 1 Jul 2021 at 18:22, Jim Lemon wrote:
> > Hi Jeremie,
> > Try:
> >
> > as.Date("20-12-2020","%y-%m-%d")
> > [1] "2020-12-20"
>
> Thanks for this info. I'm looking for something that produce NA if the date
> is
> not exactly in the specified format so that it can be corrected. I was
> relying on
> the format parameter of the date for that.
>
> The issue is that there can be so many variations in date format that for
> the
> time being I still find it easier to delegate the correction to the user. A
> particular nasty case is when there are multiple date format in the same
> column.
>
>
> Best regards,
> Jeremie
__
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and provide commented, minimal, self-contained, reproducible code.
Re: [R] Unexpected date format coercion
Hello
On Thursday, 1 Jul 2021 at 08:25, PIKAL Petr wrote:
> Hm.
>
> Seems to me, that both your codes are wrong but printing in Linux is
> different from Windows.
>
> With
> as.Date("20-12-2020","%Y-%m-%d")
> you say that 20 is year (actually year 20) and 2020 is day and only first
> two values are taken (but with some valueas result is NA)
>
> I can confirm 4.0.3 in Windows behaves this way too.
>> as.Date("20-12-2020","%Y-%m-%d")
> [1] "0020-12-20"
Many thanks for confirming this.
On Thursday, 1 Jul 2021 at 18:22, Jim Lemon wrote:
> Hi Jeremie,
> Try:
>
> as.Date("20-12-2020","%y-%m-%d")
> [1] "2020-12-20"
Thanks for this info. I'm looking for something that produce NA if the
date is not exactly in the specified format so that it can be
corrected. I was relying on the format parameter of the date for that.
The issue is that there can be so many variations in date format that for the
time
being I still find it easier to delegate the correction to the user. A
particular nasty case is when there are multiple date format in the same
column.
Best regards,
Jeremie
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Unexpected date format coercion
Hm.
Seems to me, that both your codes are wrong but printing in Linux is
different from Windows.
With
as.Date("20-12-2020","%Y-%m-%d")
you say that 20 is year (actually year 20) and 2020 is day and only first
two values are taken (but with some valueas result is NA)
I can confirm 4.0.3 in Windows behaves this way too.
> as.Date("20-12-2020","%Y-%m-%d")
[1] "0020-12-20"
Cheers
Petr
> -Original Message-
> From: R-help On Behalf Of Jeremie Juste
> Sent: Thursday, July 1, 2021 10:06 AM
> To: r-help
> Subject: [R] Unexpected date format coercion
>
> Hello,
>
> I have been surprised when converting a character string to a date with
the
> following format,
>
> in R 4.1.0 (linux debian 10)
>
> as.Date("20-12-2020","%Y-%m-%d")
> [1] "20-12-20"
>
> in R 4.0.5 (window 10)
>
> as.Date("20-12-2020","%Y-%m-%d")
> [1] "0020-12-20"
>
>
> Here I was expecting a blunt and sharp NA, am I missing something?
>
> Best regards,
> Jeremie
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.
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Re: [R] Unexpected date format coercion
Hi Jeremie,
Try:
as.Date("20-12-2020","%y-%m-%d")
[1] "2020-12-20"
Jim
On Thu, Jul 1, 2021 at 6:16 PM Jeremie Juste wrote:
>
> Hello,
>
> I have been surprised when converting a character string to a date with the
> following
> format,
>
> in R 4.1.0 (linux debian 10)
>
> as.Date("20-12-2020","%Y-%m-%d")
> [1] "20-12-20"
>
> in R 4.0.5 (window 10)
>
> as.Date("20-12-2020","%Y-%m-%d")
> [1] "0020-12-20"
>
>
> Here I was expecting a blunt and sharp NA, am I missing something?
>
> Best regards,
> Jeremie
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
__
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Re: [R] Unexpected date format coercion
On 01.07.2021 10:06, Jeremie Juste wrote:
Hello,
I have been surprised when converting a character string to a date with the
following
format,
in R 4.1.0 (linux debian 10)
as.Date("20-12-2020","%Y-%m-%d")
[1] "20-12-20"
in R 4.0.5 (window 10)
as.Date("20-12-2020","%Y-%m-%d")
[1] "0020-12-20"
Yes, it is rather strange to specify "2020" as the day and "20" as the
4digits year, so different implementations may print the year in 2 or 4
digits. What you want is actually
as.Date("20-12-2020","%d-%m-%Y")
Best,
Uwe Ligges
Here I was expecting a blunt and sharp NA, am I missing something?
Best regards,
Jeremie
__
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and provide commented, minimal, self-contained, reproducible code.
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R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
[R] Unexpected date format coercion
Hello,
I have been surprised when converting a character string to a date with the
following
format,
in R 4.1.0 (linux debian 10)
as.Date("20-12-2020","%Y-%m-%d")
[1] "20-12-20"
in R 4.0.5 (window 10)
as.Date("20-12-2020","%Y-%m-%d")
[1] "0020-12-20"
Here I was expecting a blunt and sharp NA, am I missing something?
Best regards,
Jeremie
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
