[R] Need help on changing a table

John Kane jrkrideau at yahoo.ca
Sat Dec 1 21:36:17 CET 2007


That's no table that's a data.frame :). 

For what you want probably the easiest way is 
aggregate.  Type ?aggregate for the help information

Based on your example and assuming the data is called
"mydata" this shold do what you want.


aggregate(mydata[,2:3], by=list(item=mydata$Item),
sum)


--- gsmkb86 <gsmkb_86 at hotmail.com> wrote:

> 
> Hi all:
> Im kind of new on R and I need help changing a
> table. The thing is, i read a
> file on R using the read.table command and the table
> looks like this:
> Item      3d Plot     XY plot    
> 001          1             0            
> 001          0             1            
> 001          0             1      
> 002          1             0
> 002          1             0
> 002          0             1
> ...            ..             ..
> And what I want to do is generate a new table by
> item with the sum of the
> numbres, the next one is an example:
> 
> Item     3d Plot       XY plot
> 001          1              2
> 002          2              1
> 003          ...            ...
> 
> Does anyone know how to do this? Thanks in advance,
> help is greatly
> appreciated



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