[R] sort dates within a factor

[Stefan Uhmann]

Hi,

late, but here is the feedback.
plyr was the way to go, but given my large df, plyr crashed when I
applied it to the whole df. So I just took the part of the df to sort,
applied plyr to it and then merged it with the original df.

Thank you, Xavier & Hadley!
Stefan

xavier.chardon at free.fr schrieb, Am 29.09.2009 13:58:
> Apologies for the misunderstanding. I can come up with a solution that might suit your needs:
> 
> library(plyr)
> out <- ddply(test, .(nr), function(x) data.frame(date=x$date, index=rank(-as.integer(x$date))))
> out[is.na(out$nr) | is.na(out$date), "index"] <- NA
> 
> Xavier
> 
> ----- Mail Original -----
> De: "Stefan Uhmann" <stefan.uhmann at googlemail.com>
> À: r-help at r-project.org
> Envoyé: Mardi 29 Septembre 2009 13h15:10 GMT +01:00 Amsterdam / Berlin / Berne / Rome / Stockholm / Vienne
> Objet: Re: [R] sort dates within a factor
> 
> Hi Xavier,
> 
> thank you for your suggestion, it's not exactly what I need. However I 
> made some progress using tapply, but it does not give me the 'correct' 
> result (see index - that's what I want to obtain!) when NAs are involved:
> 
> test <- data.frame(date =
> as.Date(c('2007-01-01','2008-03-24','NA','2003-03-02','2004-01-01','2008-05-03','2002-05-23','2001-06-30','2005-12-04')),
> 	nr = c(2000,2000,2000,2000,NA,2001,2002,2003,2003))
> test
> # the result should look like:
> cbind(test, index = c(2,1,NA,3,NA,1,1,2,1))
> # tapply does not treat NAs as intended
> unlist(tapply(test$date, test$nr, function(x){order(x, decreasing = T)}))
> 
> Kind Regards,
> Stefan
> 
> xavier.chardon at free.fr schrieb, Am 29.09.2009 12:12:
>> Is this what you want?
>>
>> test[order(test$nr, -as.integer(test$date)),]
>>
>> Xavier
>>
>> ----- Mail Original -----
>> De: "Stefan Uhmann" <stefan.uhmann at googlemail.com>
>> À: r-help at r-project.org
>> Envoyé: Mardi 29 Septembre 2009 11h27:20 GMT +01:00 Amsterdam / Berlin / Berne / Rome / Stockholm / Vienne
>> Objet: [R] sort dates within a factor
>>
>> Dear List,
>>
>> I have the following data:
>>
>>  >>
>> test <- data.frame(date = 
>> as.Date(c('2007-01-01','2008-03-24','2003-03-02','2008-05-03','2002-05-23','2001-06-30','2005-12-04')),
>> 	nr = c(2000,2000,2000,2001,2002,2003,2003))
>> test
>>          date   nr
>> 1 2007-01-01 2000
>> 2 2008-03-24 2000
>> 3 2003-03-02 2000
>> 4 2008-05-03 2001
>> 5 2002-05-23 2002
>> 6 2001-06-30 2003
>> 7 2005-12-04 2003
>> <<
>>
>> and would like a result which looks as follows, i.e. that sorts the 
>> dates within the factor starting with the last one:
>>
>>  >>
>> cbind(test, index = c(2,1,3,1,1,2,1))
>> <<
>>
>>          date   nr index
>> 1 2007-01-01 2000     2
>> 2 2008-03-24 2000     1
>> 3 2003-03-02 2000     3
>> 4 2008-05-03 2001     1
>> 5 2002-05-23 2002     1
>> 6 2001-06-30 2003     2
>> 7 2005-12-04 2003     1
>>
>> I've done sth. similar before, but I have difficulties to figure it out 
>> this time.
>>
>> Thanks for your help in advance!
>>
>> Regards,
>> Stefan
>>
>> ______________________________________________
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> 
> ______________________________________________
> 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.