On Dec 16, 2008, at 8:49 AM, Prof Brian Ripley wrote:
On Tue, 16 Dec 2008, David Winsemius wrote:
You cannot keep them as strings and still get the benefits of
working with date-class objects. You should read more documentation
regarding dates. The
You can: order() will work on the Date class and the ordering can be
applied to the original data.
Got it. Worked examples:
> dts <- c("10-02-2008", "10-03-2008", "10-06-2008", "10-07-2008",
"10-09-2008", "12-09-2008", "12-10-2008", "12-11-2008", "12-12-2008",
"12-15-2008","4-18-2008", "4-21-2008", "4-22-2008", "4-23-2008")
> order(as.Date(dts, format = "%m-%d-%Y"))
[1] 11 12 13 14 1 2 3 4 5 6 7 8 9 10
> rev(order(as.Date(dts, format = "%m-%d-%Y")))
[1] 10 9 8 7 6 5 4 3 2 1 14 13 12 11
> dts[rev(order(as.Date(dts, format = "%m-%d-%Y")))]
[1] "12-15-2008" "12-12-2008" "12-11-2008" "12-10-2008" "12-09-2008"
"10-09-2008" "10-07-2008" "10-06-2008" "10-03-2008"
[10] "10-02-2008" "4-23-2008" "4-22-2008" "4-21-2008" "4-18-2008"
> dts[order(as.Date(dts, format = "%m-%d-%Y"))]
[1] "4-18-2008" "4-21-2008" "4-22-2008" "4-23-2008" "10-02-2008"
"10-03-2008" "10-06-2008" "10-07-2008" "10-09-2008"
[10] "12-09-2008" "12-10-2008" "12-11-2008" "12-12-2008" "12-15-2008"
I still suggest that RON70 educate himself further regarding the Date
class and formats.
--
David Winsemius
as.Date function turns strings into a form that is stored
internally as number of days since some reference date and what you
are seeing is the default display format, %Y-%m-%d". Learn how to
use the output formats so that you see what you desire.
?as.Date
?Dates
?format.Date
--
David Winsemius
On Dec 16, 2008, at 8:24 AM, RON70 wrote:
Yes you are right. However using that code, format of date is
altered. I need
to main same format as the input data i.e. "10-02-2008" not
"2008-10-02",
still having date-class. Any better idea?
David Winsemius wrote:
You might want to look at your date format more closely. Both the
separator and the year format specs fail to match your input.
as.Date("10-02-2008", format = "%m/%d/%y")
[1] NA
as.Date("10-02-2008", format = "%m-%d-%Y")
[1] "2008-10-02"
--
David Winsemius
On Dec 16, 2008, at 7:54 AM, RON70 wrote:
I have a date-like-vector like :
date_file
"10-02-2008" "10-03-2008" "10-06-2008" "10-07-2008" "10-09-2008"
"10-10-2008" "10-13-2008" "10-14-2008" "10-15-2008"
"10-16-2008" "10-17-2008" "10-20-2008" "10-21-2008" "10-22-2008"
"10-23-2008" "10-24-2008" "10-28-2008" "10-29-2008"
"10-30-2008" "10-31-2008" "11-03-2008" "11-04-2008" "11-05-2008"
"11-06-2008" "11-07-2008" "11-10-2008" "11-11-2008"
"11-12-2008" "11-13-2008" "11-14-2008" "11-17-2008" "11-18-2008"
"11-19-2008" "11-20-2008" "11-21-2008" "11-24-2008"
"11-25-2008" "11-26-2008" "11-28-2008" "12-01-2008" "12-02-2008"
"12-03-2008" "12-04-2008" "12-05-2008" "12-08-2008"
"12-09-2008" "12-10-2008" "12-11-2008" "12-12-2008" "12-15-2008"
"4-18-2008" "4-21-2008" "4-22-2008" "4-23-2008"
"4-24-2008" "4-28-2008" "4-29-2008" "5-01-2008" "5-05-2008"
"5-06-2008" "5-07-2008" "5-09-2008" "5-12-2008"
"5-13-2008" "5-14-2008" "5-15-2008" "5-16-2008" "5-19-2008"
"5-20-2008" "5-21-2008" "5-22-2008" "5-23-2008"
"5-27-2008" "5-28-2008" "5-29-2008" "5-30-2008" "6-02-2008"
"6-03-2008" "6-05-2008" "6-06-2008" "6-09-2008"
"6-10-2008" "6-11-2008" "6-12-2008" "6-13-2008" "6-17-2008"
"6-18-2008" "6-19-2008" "6-20-2008" "6-23-2008"
"6-24-2008" "6-25-2008" "6-26-2008" "6-27-2008" "7-01-2008"
"7-02-2008" "7-04-2008" "7-07-2008" "7-08-2008"
"7-09-2008" "7-10-2008" "7-11-2008" "7-15-2008" "7-16-2008"
"7-18-2008" "7-21-2008" "7-22-2008" "7-23-2008"
"7-24-2008" "7-25-2008" "7-28-2008" "7-30-2008" "7-31-2008"
"8-01-2008" "8-04-2008" "8-05-2008" "8-06-2008"
"8-07-2008" "8-08-2008" "8-11-2008" "8-12-2008" "8-13-2008"
"8-15-2008" "8-18-2008" "8-19-2008" "8-20-2008"
"8-21-2008" "8-22-2008" "8-25-2008" "8-26-2008" "8-27-2008"
"8-28-2008" "8-29-2008" "9-03-2008" "9-04-2008"
"9-05-2008" "9-08-2008" "9-09-2008" "9-10-2008" "9-11-2008"
"9-12-2008" "9-15-2008" "9-16-2008" "9-17-2008"
"9-18-2008" "9-19-2008" "9-22-2008" "9-23-2008" "9-24-2008"
"9-25-2008" "9-26-2008" "9-29-2008" "9-30-2008"
I wanted to sort this in ascending order. I tried using simply
sort()
function, without altering the format of date, but it didnot work.
Next I
tried to convert that vector in a date-class vector so that, I
could
sort
them but in vein :(
I used :
as.Date(date_file, format="%m/%d/%y")
However it did not work.
Can anyone please tell me what would be correct approach?
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______________________________________________
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PLEASE do read the posting guide
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View this message in context:
http://www.nabble.com/Sorting-a-date-vector-tp21032540p21032997.html
Sent from the R help mailing list archive at Nabble.com.
______________________________________________
R-help@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.
______________________________________________
R-help@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.
--
Brian D. Ripley, rip...@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
______________________________________________
R-help@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.
