Aggregate R sum

Question

I\'m writting my first program in R and as a newbie I\'m having some troubles, hope you can help me.

I\'ve got a data frame like this:

> v1<-c         


        

Answer 1

You need to tell the aggregate function to use sum, as the default is for it to get the mean of each category. For example:

aggregate(datos[,c("a1","a2","a3")], by=list(datos$Position), "sum")