[R] How to order based on the second two columns?

[David Winsemius]

On Aug 29, 2011, at 2:40 PM, Andra Isan wrote:

> Hello All,
>
> I have a data frame consisting of 4 columns (id1, id2, y, pred)
> where pred is the predicted value based on the glm function and my  
> data frame is called "all". "data" is another data frame that has  
> all data but I want to put together some important columns from my  
> original data frame (data) into another data frame (all) as follows  
> and I would like them to be sorted based on the id1 and id2. Here is  
> what I do:
>
> all_data = cbind(oder(data[,2]), order(data[,3]), data[,1], pred)
> all = as.data.frame(all_data)
> colnames(all) = c("id1", "id2", "y" , "pred")
>
> when I do the ordering thing, I am not sure why I do not get the  
> corresponding "y" and "pred" values for that specific row after  
> ordering. Am I doing something wrong in here?

Your error is in not using 'merge' instead of 'cbind'.

-- 
David Winsemius, MD
West Hartford, CT