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

[Uwe Ligges]

Xin wrote:
> Dear All:
> 
>     I imported a table into R. But I want to read a variable (y) from this table conditional on another variable (x=1) in the table.
> 
> y<-data[,7]
> x<-data[,3]
> 
> I want to know the mean of y if corresponding x=1.
> 
> I tried 
> 
> if (x==1) y3<-y 
> 
> It does not work.
> 
> Anyone can give a help?

Is this homework?
Please do read the posting guide and An Introduction to R!

Uwe Ligges


 > Thanks!
> 
> 
> Xin
> 	[[alternative HTML version deleted]]
> 
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