[R] a < b < c is alway TRUE
Bill Oliver
wloliver at qwest.net
Fri Jul 6 15:29:38 CEST 2001
----- Original Message -----
From: "Till Baumgaertel" <till.baumgaertel at epost.de>
To: <r-help at stat.math.ethz.ch>
Cc: "Uwe Ligges" <ligges at statistik.uni-dortmund.de>
Sent: Friday, July 06, 2001 5:21 AM
Subject: Re: [R] a < b < c is alway TRUE
> > 3 < 2 < 1 # [1] TRUE ???
> this is evaluated from left to right:
> (3<2)<1
>
> 3<2 = FALSE
> FALSE<1 = TRUE
>
> what's surprising is the following:
> > FALSE<1
> [1] TRUE
> > FALSE>1
> [1] FALSE
> > TRUE<1
> [1] FALSE
> > TRUE>1
> [1] FALSE
>
> because of symmetry i'd expect TRUE>1 to be TRUE.
TRUE is being treated as equal to 1, so TRUE >= 1, returns TRUE. However,
non-zero values are treated as TRUE when coercing numerical values.
> as.logical(c(-2,-1,-.5,0,.5,1,2))
[1] TRUE TRUE TRUE FALSE TRUE TRUE TRUE
-Bill
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