# Re: [R] question about date's

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Tue 13 Dec 2005 - 00:09:12 EST

On Mon, 12 Dec 2005, ronggui wrote:

>> x<-as.Date(c("2005-07-01", "2005-07-02","2005-07-03","2005-07-04","2005-07-05"))
>> weekdays(x)
> [1] "星期五" "星期六" "星期日" "星期一" "星期二"
>
>> months(x)
> [1] "七月" "七月" "七月" "七月" "七月"

He asked for week numbers. That's nothing like as easy, as it is not well-defined. But

> strftime(as.POSIXlt(x), "%U")

[1] "26" "26" "27" "27" "27"

is one possibility ("%W" is another). This approach will do the other requests just as easily.

> ======= 2005-12-12 20:17:38 您在来信中写道：=======
>
>> Thanks!
>> That solves my problem for year numbers and month numbers
>> Any idea how to do this for week numbers?
>>
>> Regards,
>> Richard
>>
>> On 12/12/05, ronggui <042045003@fudan.edu.cn> wrote:
>>> This is one way to do it.
>>>> x<-c("2005-07-01", "2005-07-02","2005-07-03","2005-07-04","2005-07-05")
>>>> x
>>> [1] "2005-07-01" "2005-07-02" "2005-07-03" "2005-07-04" "2005-07-05"
>>>> substr(x,1,4)
>>> [1] "2005" "2005" "2005" "2005" "2005"
>>>> substr(x,6,7)
>>> [1] "07" "07" "07" "07" "07"
>>>> substr(x,9,10)
>>> [1] "01" "02" "03" "04" "05"
>>>>
>>>
>>>
>>> ======= 2005-12-12 20:06:00 您在来信中写道：=======
>>>
>>>> Hi,
>>>>
>>>> Given a frame with calendar date's:
>>>>
>>>> "2005-07-01", "2005-07-02","2005-07-03","2005-07-04","2005-07-05",etc.
>>>>
>>>> I want to extract the following from these dates:
>>>>
>>>> week number
>>>> month number
>>>> year number
>>>>
>>>> Any ideas how to accomplish this?
>>>>
>>>> Many thanks.
>>>>
>>>> Regards,
>>>> Richard
>>>>
>>>> ______________________________________________
>>>> R-help@stat.math.ethz.ch mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>
>>> = = = = = = = = = = = = = = = = = = = =
>>>
>>>
>>>
>>>
>>>
>>> 2005-12-12
>>>
>>> ------
>>> Deparment of Sociology
>>> Fudan University
>>>
>>> My new mail addres is ronggui.huang@gmail.com
>>> Blog:http://sociology.yculblog.com
>>>
>
> = = = = = = = = = = = = = = = = = = = =
>
>
>
>
>
> 2005-12-12
>
> ------
> Deparment of Sociology
> Fudan University
>
> My new mail addres is ronggui.huang@gmail.com
> Blog:http://sociology.yculblog.com
>
>

--
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Tue Dec 13 00:19:36 2005

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