[R] Calculate of data frame
Zhang, Fan
fzhang at doubleclick.net
Thu Jul 14 20:26:38 CEST 2005
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 at pubhealth.ku.dk [mailto:pd at pubhealth.ku.dk] On Behalf Of Peter Dalgaard
Sent: Thursday, July 14, 2005 1:29 PM
To: Zhang, Fan
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] Calculate of data frame
"Zhang, Fan" <fzhang at 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 Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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