Yes, I am seeing that at the end of 2010-beginning 2011. Try:
weekdays(as.POSIXct("2010-12-25")+(0:20)*24*60*60)
week(as.POSIXct("2010-12-25")+(0:20)*24*60*60)
Week 1 (2011) is made up of 6 days....
Luca
Il giorno 20/dic/2010, alle ore 17.54, David Winsemius ha scritto:
>
> On Dec 20, 2010, at 10:58 AM, Luca Meyer wrote:
>
>> Right, I appreciate the first day of the year start date. I am just
>> wondering why then the cut off day is not the same for the rest of the
>> year...but it's all right to use other packages.
>
> Are you saying it shifts within the year? I am not seeing that:
>
> require(lubridate)
>
> > weekdays(as.POSIXct("2010-01-01")+(0:8)*24*60*60)
> [1] "Friday" "Saturday" "Sunday" "Monday" "Tuesday" "Wednesday"
> [7] "Thursday" "Friday" "Saturday"
> > week(as.POSIXct("2010-01-01")+(0:8)*24*60*60)
> [1] 1 1 1 1 1 1 2 2 2
>
> Looks to be incrementing weeks between Wed and Thurs at the beginning of the
> year just as it did in your example. I admit that I thought that it should be
> shifting at the Thursday - Friday divide, but setting a zero point can be
> ambiguous. I thought if it were Midnight Thursday-Friday that all of
> Thurdays would be in week 1. But at least it appears consistent.
>
>
>> Thanks,
>> Luca
>>
>> Il giorno 20/dic/2010, alle ore 14.16, David Winsemius ha scritto:
>>
>>>
>>> On Dec 20, 2010, at 12:54 AM, Luca Meyer wrote:
>>>
>>>> All right, I get it now: lubridate's week() define weeks from Thursday
>>>> till the following Wednesday. You'd probably agree with me that it's a bit
>>>> strange what it is going to do over the turn of the year:
>>>>
>>>>> y <-
>>>>> as.POSIXct(c("2010-12-27","2010-12-28","2010-12-29","2010-12-30","2010-12-31","2011-01-01","2011-01-02","2011-01-03","2011-01-04","2011-01-05","2011-01-06","2011-01-07","2011-01-08","2011-01-09","2011-01-10","2011-01-11","2010-01-12","2010-01-13","2010-01-14"))
>>>>> week(y)
>>>> [1] 52 52 52 53 53 1 1 1 1 1 1 2 2 2 2 2 2 2 3
>>>>
>>>> Why would the first week of the year be made of 6 days and the turn from
>>>> week 1 to week 2 on the night between Thursday and Friday and not
>>>> Wednesday and Friday like every other week?
>>>
>>> weeks in lubridate start on whatever day of the week is the first of that
>>> year.
>>>
>>> If you want a Monday starting day (or the option to change to another
>>> starting day), then package chron has such facilities.
>>>
>>>
>>>>
>>>> Cheers,
>>>> Luca
>>>>
>>>>
>>>>
>>>> Il giorno 19/dic/2010, alle ore 18.14, Uwe Ligges ha scritto:
>>>>
>>>>>
>>>>>
>>>>> On 19.12.2010 13:20, David Winsemius wrote:
>>>>>>
>>>>>> On Dec 19, 2010, at 5:11 AM, Luca Meyer wrote:
>>>>>>
>>>>>>> Something goes wrong with the week function of the lubridate package:
>>>>>>>
>>>>>>>> x= as.POSIXct(factor(c("2010-12-15 17:28:27",
>>>>>>> + "2010-12-15 17:32:34",
>>>>>>> + "2010-12-15 18:48:39",
>>>>>>> + "2010-12-15 19:25:00",
>>>>>>> + "2010-12-16 08:00:00",
>>>>>>> + "2010-12-16 08:25:49",
>>>>>>> + "2010-12-16 09:00:00")))
>>>>>>>> require(lubridate)
>>>>>>
>>>>>>>> weekdays(x)
>>>>>>> [1] "Mercoledì" "Mercoledì" "Mercoledì" "Mercoledì" "Giovedì"
>>>>>>> "Giovedì" "Giovedì"
>>>>>>>> week(x)
>>>>>>> [1] 50 50 50 50 51 51 51
>>>>>>
>>>>>> But 2010-12-15 is a Wednesday and 2010-12-16 is a Thursday.
>>>>>>
>>>>>
>>>>>
>>>>> Together with the description of ?week this shows that lubridate's week()
>>>>> function works as documented rather than as expected by Luca Meyer.
>>>>>
>>>>> Uwe Ligges
>>>>
>>>
>>> David Winsemius, MD
>>> West Hartford, CT
>>>
>>
>
> David Winsemius, MD
> West Hartford, CT
>
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