[R] a < b < c is alway TRUE

Peter Malewski peter.malewski at gmx.de
Fri Jul 6 12:50:44 CEST 2001




I forgot the explanation: R (and s+3) evalutes from left to right and 
converts logical to numeric. see below.


On Fri, Jul 06, 2001 at 12:48:01PM +0200, Peter Malewski wrote:
> 
> > 3 < 2
> [1] FALSE
> > F < 1
> [1] TRUE
> > as.numeric(F)
> [1] 0
> 
> 
> p.
> 
> 
> On Fri, Jul 06, 2001 at 12:08:51PM +0200, Monika Ferster wrote:
> > Uwe Ligges writes:
> >  > One of our students did something like:
> >  > 
> >  >   x[a < b < c]
> >  > 
> >  > instead of 
> >  > 
> >  >   x[a < b & b < c]
> >  > 
> >  > 
> >  > But why is
> >  > 
> >  >   3 < 2 < 1	# [1] TRUE ???
> >  > 
> > 
> > 3 < 2 < 1 seems to be seen like a double no because 3 < 2 < 1 < 0 returns
> > F. It looks like the multiplication of -1 what is strange, because F
> > corresponds to the value 0. So if you do (3<2)*(2<1) you get 0 and not the
> > value of T (=1).
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> -- 
> P.Malewski, Limmerstr.47, 30451 Hannover, 0511-2135008
> At work: http://www.MH-Hannover.de 0511 532 3194 / Fax: 0511 532 3190, 
> P.Malewski at tu-bs.de, peter.malewski at gmx.de, malewski.peter at mh-hannover.de.

-- 
P.Malewski, Limmerstr.47, 30451 Hannover, 0511-2135008
At work: http://www.MH-Hannover.de 0511 532 3194 / Fax: 0511 532 3190, 
P.Malewski at tu-bs.de, peter.malewski at gmx.de, malewski.peter at mh-hannover.de.
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