Neil, Maybe this example will make things more clear to you.
> DF <- expand.grid(A = 0:1, B = 0:1) > cbind(DF, DF$A != 0, DF$B != 0, DF$A != 0 & DF$B != 0, DF$A != 0 | DF$B != 0) A B DF$A != 0 DF$B != 0 DF$A != 0 & DF$B != 0 DF$A != 0 | DF$B != 0 1 0 0 FALSE FALSE FALSE FALSE 2 1 0 TRUE FALSE FALSE TRUE 3 0 1 FALSE TRUE FALSE TRUE 4 1 1 TRUE TRUE TRUE TRUE Thierry ------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 [EMAIL PROTECTED] www.inbo.be Do not put your faith in what statistics say until you have carefully considered what they do not say. ~William W. Watt A statistical analysis, properly conducted, is a delicate dissection of uncertainties, a surgery of suppositions. ~M.J.Moroney -----Oorspronkelijk bericht----- Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Namens Neil Shephard Verzonden: maandag 25 februari 2008 15:36 Aan: ONKELINX, Thierry CC: r-help Onderwerp: Re: [R] Logical statements and subseting data... Thanks Thierry, they do both leave me with what I expected. On Mon, Feb 25, 2008 at 2:28 PM, ONKELINX, Thierry <[EMAIL PROTECTED]> wrote: > The negation of Height.1 == 0 & Height.2 == 0 was incorrect. Use > > subset(raw.all.clean, !(Height.1 == 0 & Height.2 == 0)) I can see clearly how this expression works (negating the whole test), but... > or > > subset(raw.all.clean, Height.1 != 0 | Height.2 != 0) ...not how this works, since the above to me is saying Height.1 is NOT zero OR Height.2 is NOT zero, which to my mind would pick out samples where either one or the other is not equal to zero (and of course those instances where both are equal to zero)? It seems to me that & (AND) and | (OR) are used the wrong way round in this case, since the intersection of the two tests for inequality is what is required? Neil -- Email - [EMAIL PROTECTED] / [EMAIL PROTECTED] ______________________________________________ R-help@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. ______________________________________________ R-help@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.