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.
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
>
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