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
  ÂÃ‰cole d'actuariat
  UniversitÂÃ© Laval, QuÂÃ©bec
  Vincent.Goulet at act.ulaval.ca   http://vgoulet.act.ulaval.ca

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Testing if all elements are equal in a vector/matrix

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