[R] Summarizing For Values with Multiple categories

[Alison Waller]

Hi all,

I have some data as follows.

Cat1 Cat2 Cat3  COG Counts
    A    B    C COG1     10
    B    D      COG2     20
    C           COG3     30
    D           COG4     40

I would like to sum all the counts for each category:
A	B	C	D
10	30	40	60

 >CAT2COG<- 
list(A="COG1",B=c("COG1","COG2"),C=c("COG1","COG3"),D=c("COG2","COG4"))
 > COG2CAT<- 
list(COG1=c("A","B","C"),COG2=c("B","D"),COG3=c("C"),COG4="D")
 > df<- 
data.frame(COGs=c("COG1","COG2","COG3","COG4"),counts=c(10,20,30,40))


I've been trying various version of apply and well as some crazy loops  
(Eg. below).

Any help would be appreciated

Thanks,

Alison
 > CATS<-names(CAT2COG)
 > Catcounts<-rep(0,length(CATS))
 > counter<-1
 > for (i in CATS){
+ Catcounts[counter]<-CatCounts+df$counts[df[1,]=CAT2COG[i],]
Error: syntax error
 > counter<-counter+1
 > }