From: Zhang, Fan <fzhang_at_doubleclick.net>

Date: Fri 15 Jul 2005 - 04:26:38 EST

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 15 04:29:16 2005

Date: Fri 15 Jul 2005 - 04:26:38 EST

Thanks for your answer, Peter. Now I have a new data frame which is sorted by (model,date) pair. Since the sorting is done to charactors, I have 7/1/2005 followed by 7/10/2005 instead of 7/2/2005. How can I do the aggregation and at the same time, make the result sorted the way I want (i.e, 7/1/2005 followd by 7/2/2005)?

Thanks,

Fan

-----Original Message-----

From: pd@pubhealth.ku.dk [mailto:pd@pubhealth.ku.dk] On Behalf Of Peter Dalgaard
Sent: Thursday, July 14, 2005 1:29 PM

To: Zhang, Fan

Cc: r-help@stat.math.ethz.ch

Subject: Re: [R] Calculate of data frame

"Zhang, Fan" <fzhang@doubleclick.net> writes:

> Now I want to get the total count and value for each model/date pair,

*> like
**> model count value date
**> A 6 31.8 7/1/2005
**> A 3 10.2 7/2/2005
**> B 7 14.2 7/1/2005
**> B 10 67.4 7/2/2005
**>
**> Anyone can tell me how to do this?
*

> aggregate(df[,c("count","value")],df[,c("date","model")],sum)

date model count value 1 7/1/2005 A 6 31.8 2 7/2/2005 A 3 10.2 3 7/1/2005 B 7 14.2 4 7/2/2005 B 10 71.4 -- O__ ---- Peter Dalgaard ุster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907 ______________________________________________R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 15 04:29:16 2005

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