FAQ 7.31 On Wed, Aug 27, 2008 at 11:51 AM, David Afshartous <dafshartous at med.miami.edu> wrote:> > All, > > I'm witnessing some strange behavior when checking the values of one of my > variables. My guess is that it has something to do with the number of > significant digits being represented, but perhaps not as my variable was > created from other variables that only had one decimal place. See below. > I'm sure this is something basic, any suggestions much appreciated. > > Cheers, > David > > >> visit.2.SEK.delta.baseline > [1] 0.1 -0.7 0.8 -0.1 -0.5 0.8 0.7 0.2 0.4 0.3 0.6 0.6 0.3 0.8 > 0.8 0.3 0.4 0.8 >> visit.2.SEK.delta.baseline > 0 > [1] TRUE FALSE TRUE FALSE FALSE TRUE TRUE TRUE TRUE TRUE TRUE TRUE > TRUE TRUE TRUE TRUE TRUE TRUE >> visit.2.SEK.delta.baseline == .8 > [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE > FALSE FALSE FALSE FALSE FALSE FALSE > ### but some of the values are equal to .8 > > ## here it is okay when I try to reproduce >> junk = c(0.1, -0.7,0.8, -0.1, -0.5, 0.8, 0.7, 0.2, 0.4, 0.3, 0.6, 0.6, > 0.3, 0.8, 0.8, 0.3, 0.4, 0.8 ) >> junk == .8 > [1] FALSE FALSE TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE > FALSE TRUE TRUE FALSE FALSE TRUE > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve?
David Afshartous
2008-Aug-27 15:51 UTC
[R] Significant digits for checking values of variable?
All, I'm witnessing some strange behavior when checking the values of one of my variables. My guess is that it has something to do with the number of significant digits being represented, but perhaps not as my variable was created from other variables that only had one decimal place. See below. I'm sure this is something basic, any suggestions much appreciated. Cheers, David> visit.2.SEK.delta.baseline[1] 0.1 -0.7 0.8 -0.1 -0.5 0.8 0.7 0.2 0.4 0.3 0.6 0.6 0.3 0.8 0.8 0.3 0.4 0.8> visit.2.SEK.delta.baseline > 0[1] TRUE FALSE TRUE FALSE FALSE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE> visit.2.SEK.delta.baseline == .8[1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE ### but some of the values are equal to .8 ## here it is okay when I try to reproduce> junk = c(0.1, -0.7,0.8, -0.1, -0.5, 0.8, 0.7, 0.2, 0.4, 0.3, 0.6, 0.6,0.3, 0.8, 0.8, 0.3, 0.4, 0.8 )> junk == .8[1] FALSE FALSE TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE TRUE TRUE FALSE FALSE TRUE