R help - Apr 2010 - format() method

Hello,
I use format() function to get number of the week, like this:
format(tmp,'%U')
Recently, I have spotted something bizarre. For example, I have such object:
(index(tmp$x.delta['2009'][1:16]))
 [1] "2009-01-02 CET"  "2009-01-09 CET"  "2009-01-16
CET"  "2009-01-23 CET"
 [5] "2009-01-30 CET"  "2009-02-06 CET"  "2009-02-13
CET"  "2009-02-20 CET"
 [9] "2009-02-27 CET"  "2009-03-06 CET"  "2009-03-13
CET"  "2009-03-20 CET"
[13] "2009-03-27 CET"  "2009-04-03 CEST" "2009-04-09
CEST" "2009-04-17 CEST"
dput(index(tmp$x.delta['2009'][1:16]),'%U',file='as.date')
structure(c(1230850800, 1231455600, 1232060400, 1232665200, 1233270000, 
1233874800, 1234479600, 1235084400, 1235689200, 1236294000, 1236898800, 
1237503600, 1238108400, 1238709600, 1239228000, 1239919200), tzone
structure("", .Names = "TZ"), class = c("POSIXt",
"POSIXct"))
To get number of the week I run:
format(index(tmp$x.delta['2009'][1:16]),'%U')
Here is the output - the weird thing is, that the first number of the week
is 00.
 [1] "00" "01" "02" "03" "04"
"05" "06" "07" "08" "09"
"10" "11" "12" "13"
"14"
[16] "15"

Is it the bug, my mistake or it is supposed to by like that?
Thank you,
kafka
-- 
View this message in context:
http://n4.nabble.com/format-method-tp1999753p1999753.html
Sent from the R help mailing list archive at Nabble.com.

Were you expecting "01", and is that why you are puzzled?

See ?strftime and the explanation of the %U format. It depends on 
where the first Sunday of the year happens to fall.

-Don

At 5:28 AM -0800 4/16/10, kafkaz wrote:
>Hello,
>I use format() function to get number of the week, like this:
>format(tmp,'%U')
>Recently, I have spotted something bizarre. For example, I have such object:
>(index(tmp$x.delta['2009'][1:16]))
>  [1] "2009-01-02 CET"  "2009-01-09 CET" 
"2009-01-16 CET"  "2009-01-23 CET"
>  [5] "2009-01-30 CET"  "2009-02-06 CET" 
"2009-02-13 CET"  "2009-02-20 CET"
>  [9] "2009-02-27 CET"  "2009-03-06 CET" 
"2009-03-13 CET"  "2009-03-20 CET"
>[13] "2009-03-27 CET"  "2009-04-03 CEST"
"2009-04-09 CEST" "2009-04-17 CEST"
>dput(index(tmp$x.delta['2009'][1:16]),'%U',file='as.date')
>structure(c(1230850800, 1231455600, 1232060400, 1232665200, 1233270000,
>1233874800, 1234479600, 1235084400, 1235689200, 1236294000, 1236898800,
>1237503600, 1238108400, 1238709600, 1239228000, 1239919200), tzone
>structure("", .Names = "TZ"), class =
c("POSIXt",
>"POSIXct"))
>To get number of the week I run:
>format(index(tmp$x.delta['2009'][1:16]),'%U')
>Here is the output - the weird thing is, that the first number of the week
>is 00.
>  [1] "00" "01" "02" "03"
"04" "05" "06" "07" "08"
"09" "10" "11" "12" "13"
>"14"
>[16] "15"
>
>Is it the bug, my mistake or it is supposed to by like that?
>Thank you,
>kafka
>--
>View this message in context: 
>http://*n4.nabble.com/format-method-tp1999753p1999753.html
>Sent from the R help mailing list archive at Nabble.com.
>
>______________________________________________
>R-help at r-project.org mailing list
>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.

-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062

On Apr 16, 2010, at 9:28 AM, kafkaz wrote:
>
> Hello,
> I use format() function to get number of the week, like this:
> format(tmp,'%U')
> Recently, I have spotted something bizarre. For example, I have such  
> object:
> (index(tmp$x.delta['2009'][1:16]))
> [1] "2009-01-02 CET"  "2009-01-09 CET" 
"2009-01-16 CET"
> "2009-01-23 CET"
> [5] "2009-01-30 CET"  "2009-02-06 CET" 
"2009-02-13 CET"
> "2009-02-20 CET"
> [9] "2009-02-27 CET"  "2009-03-06 CET" 
"2009-03-13 CET"
> "2009-03-20 CET"
> [13] "2009-03-27 CET"  "2009-04-03 CEST"
"2009-04-09 CEST"
> "2009-04-17 CEST"
>
dput(index(tmp$x.delta['2009'][1:16]),'%U',file='as.date')
> structure(c(1230850800, 1231455600, 1232060400, 1232665200,  
> 1233270000,
> 1233874800, 1234479600, 1235084400, 1235689200, 1236294000,  
> 1236898800,
> 1237503600, 1238108400, 1238709600, 1239228000, 1239919200), tzone >
structure("", .Names = "TZ"), class = c("POSIXt",
> "POSIXct"))
> To get number of the week I run:
> format(index(tmp$x.delta['2009'][1:16]),'%U')
> Here is the output - the weird thing is, that the first number of  
> the week
> is 00.
Appears to behave as documented. From ?formatPOSIXct (help page):

"%U
Week of the year as decimal number (00?53) using Sunday as the first  
day 1 of the week..."

> [1] "00" "01" "02" "03"
"04" "05" "06" "07" "08"
"09" "10" "11" "12"
> "13"
> "14"
> [16] "15"
>
> Is it the bug, my mistake or it is supposed to by like that?
> Thank you,
> kafka
-- 

David Winsemius, MD
West Hartford, CT