[R] Alternative to extended recode sintax? Bug?

[David Winsemius]

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