From: Liaw, Andy <andy_liaw_at_merck.com>

Date: Tue 20 Jul 2004 - 04:13:52 EST

*> check <- paste(names(x), collapse=" == ")
*

*> with(x, eval(parse(text=check)))
*

**[1] FALSE TRUE FALSE FALSE
**
Cheers,

Andy

R-help@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 Received on Tue Jul 20 04:31:59 2004

Date: Tue 20 Jul 2004 - 04:13:52 EST

Here's an alternative:

*> x <- data.frame(X1 = c(1, 1, 2, 4),
*

+ X2 = c(4, 1, 2, 5), + X3 = c(2, 1, 2, 2))

Andy

*> From: Sundar Dorai-Raj
**>
**> 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
**>
**> How about something like?
**>
**> x <- data.frame(X1 = c(1, 1, 2, 4),
**> X2 = c(4, 1, 2, 5),
**> X3 = c(2, 1, 2, 2))
**> nuniq <- function(x) length(unique(x))
**> as.numeric(apply(as.matrix(x), 1, nuniq) == 1)
**>
**> --sundar
**>
*

> ______________________________________________

*> R-help@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
**>
**>
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R-help@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 Received on Tue Jul 20 04:31:59 2004

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