[R] how to read data from table based a condition

[Marc Moragues]

Xin <jasonshi510 <at> hotmail.com> writes:


> 
> y<-data[,7]
> x<-data[,3]
> 
> I want to know the mean of y if corresponding x=1.
> 

Try this:

mean(data[data[,3]==1,data[,7])

You can also look at ?subset.