[R] Testing if all elements are equal in a vector/matrix

Doran, Harold
Mon, 29 Aug 2005 20:06:27 -0000

Yes, and I mistakenly thought this was comparing two objects, and that is not
the case.

-----Original Message-----
From: Francisco J. Zagmutt [mailto:gerifalte28 at hotmail.com]
Sent: Monday, August 29, 2005 4:05 PM
To: Doran, Harold; vincent.goulet at act.ulaval.ca; r-help at stat.math.ethz.ch
Subject: Re: [R] Testing if all elements are equal in a vector/matrix

Hi Doran

The documentation for isTRUE reads 'isTRUE(x)' is an abbreviation of
'identical(TRUE,x)'  so actually Vincent's solutions is
"cleaner" than using identical :)

Cheers

Francisco


>From: "Doran, Harold" <HDoran at air.org>
>To: <vincent.goulet at act.ulaval.ca>, <r-help at
stat.math.ethz.ch>
>Subject: Re: [R] Testing if all elements are equal in a vector/matrix
>Date: Mon, 29 Aug 2005 15:49:20 -0400
>
>See ?identical
>
>-----Original Message-----
>From: r-help-bounces at stat.math.ethz.ch
>[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Vincent Goulet
>Sent: Monday, August 29, 2005 3:35 PM
>To: r-help at stat.math.ethz.ch
>Subject: [R] Testing if all elements are equal in a vector/matrix
>
>
>Is there a canonical way to check if all elements of a vector or matrix
>are the same? Solutions below work, but look hackish to me.
>
> > x <- rep(1, 10)
> > all(x == x[1])  # == operator does not provide for small differences
>[1] TRUE
> > isTRUE(all.equal(x, rep(x[1], length(x)))) # ugly
>[1] TRUE
>
>Best,
>
>Vincent
>--
>   Vincent Goulet, Associate Professor
>   ??cole d'actuariat
>   Universit?? Laval, Qu??bec
>   Vincent.Goulet at act.ulaval.ca   http://vgoulet.act.ulaval.ca
>
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