[Rd] Representation of floating point numbers (PR#1281)

Göran Broström gb@stat.umu.se
Thu, 24 Jan 2002 15:15:43 +0100 (CET)

On Thu, 24 Jan 2002 theis@statistik.uni-dortmund.de wrote:

> On 24-Jan-02 Prof Brian Ripley wrote:
> > 
> > There is a function all.equal provided for this purpose: it is a misuse of
> > ==.
> But there is no hint or note on the "Comparisons" help page concerning this
> problem. If it is a misuse one should be warned against it.

But there is a warning there:

Don't use == and != for tests, such as in if expressions, where you must 
get a single TRUE or FALSE. Unless you are absolutely sure that nothing 
unusual can happen, you should use the identical function instead.

And 'identical' suggests:

> identical(all.equal(x, y), TRUE)

Clever indeed!
 Göran Broström                      tel: +46 90 786 5223
 professor                           fax: +46 90 786 6614
 Department of Statistics            http://www.stat.umu.se/egna/gb/
 Umeå University
 SE-90187 Umeå, Sweden             e-mail: gb@stat.umu.se

r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-devel-request@stat.math.ethz.ch