[R] How to compare X1 = X2 = ... = Xn?

[Uwe Ligges]

F Duan wrote:

> Dear All,
> 
>  
> 
> I have a data frame with n columns: X1, X2, ., Xn. Now I want to create a
> new column: if X1 = X2 = . = Xn, the value is 1; Otherwise, the value is 0.
> 

One idea is:

   apply(apply(X, 2, "==", X[,1]), 1, all)

but there may be better solutions.

Uwe Ligges


> 
> How to do that in a quick way instead of doing (n choose 2) comparisons? 
> 
>  
> 
> Thank you,
> 
>  
> 
> Frank
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html