[R] cbind in aggregate formula - based on an existing object (vector)
Dimitri Liakhovitski
dimitri.liakhovitski at gmail.com
Thu Jul 14 21:32:10 CEST 2011
Thank you, David, it does work.
Could you please explain why? What exactly does changing it to "as matrix" do?
Thank you!
Dimitri
On Thu, Jul 14, 2011 at 3:25 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Jul 14, 2011, at 3:05 PM, Dimitri Liakhovitski wrote:
>
>> Hello!
>>
>> I am aggregating using a formula in aggregate - of the type:
>> aggregate(cbind(var1,var2,var3)~factor1+factor2,sum,data=mydata)
>>
>> However, I actually have an object (vector of my variables to be
>> aggregated):
>> myvars<-c("var1","var2","var3")
>>
>> I'd like my aggregate formula (its "cbind" part) to be able to use my
>> "myvars" object. Is it possible?
>> Thanks for your help!
>>
>
> Not sure I have gotten all the way there, but this does work:
>
> example.agg1<-aggregate(as.matrix(example[myvars])~group+mydate,sum,data=example)
>
>> example.agg1
> group mydate example[myvars] NA
> 1 group1 2008-12-01 4 4.2
> 2 group2 2008-12-01 6 6.2
> 3 group1 2009-01-01 40 40.2
> 4 group2 2009-01-01 60 60.2
> 5 group1 2009-02-01 400 400.2
> 6 group2 2009-02-01 600 600.2
>
>> Dimitri
>>
>> Reproducible example:
>>
>> mydate = rep(seq(as.Date("2008-12-01"), length = 3, by = "month"),4)
>> value1=c(1,10,100,2,20,200,3,30,300,4,40,400)
>> value2=c(1.1,10.1,100.1,2.1,20.1,200.1,3.1,30.1,300.1,4.1,40.1,400.1)
>>
>> example<-data.frame(mydate=mydate,value1=value1,value2=value2)
>>
>> example$group<-c(rep("group1",3),rep("group2",3),rep("group1",3),rep("group2",3))
>> example$group<-as.factor(example$group)
>> (example);str(example)
>>
>>
>> example.agg1<-aggregate(cbind(value1,value2)~group+mydate,sum,data=example)
>> # this works
>> (example.agg1)
>>
>> ### Building my object (vector of 2 names - in reality, many more):
>> myvars<-c("value1","value2")
>> example.agg1<-aggregate(cbind(myvars)~group+mydate,sum,data=example)
>> ### does not work
>>
>>
>> --
>> Dimitri Liakhovitski
>> Ninah Consulting
>> www.ninah.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.
>
> David Winsemius, MD
> West Hartford, CT
>
>
--
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
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