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

[Berton Gunter]

How about:


X<-as.matrix(yourframe)
apply(X,2, '==',X[,1])%*%rep(1,ncol(X)) == ncol(x)

avoiding the rowwise apply overhead?

Cheers,

Bert Gunter

Non-Clinical Biostatistics
Genentech
MS: 240B
Phone: 650-467-7374


"The business of the statistician is to catalyze the scientific learning
process."

 -- George E.P. Box
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.
>
>
>
> How to do that in a quick way instead of doing (n choose 2) comparisons?
>
>
>
> Thank you,
>
>
>
> Frank
>
>         [[alternative HTML version deleted]]
>
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