Hi Uwe Ligges <lig...@statistik.tu-dortmund.de> napsal dne 10.06.2010 10:37:05:
> > > On 10.06.2010 10:19, Petr PIKAL wrote: > > Hi > > > > Peter Ehlers<ehl...@ucalgary.ca> napsal dne 09.06.2010 19:05:24: > > > >> Soapbox: > >> Well, if you're just starting out with R it would be > >> a VERY good idea to learn right away that T is not TRUE > >> and F is not FALSE, at least not always. Sooner or > >> later you WILL have problems. So do yourself a favour > >> and get into the habit of using TRUE/FALSE instead of T/F. > >> > >> (I know that Petr knows better.) > > > > Yes good point. However when I work interactively with command prompt I > > often (well almost exclusively :-) use T/F instead of TRUE/FALSE as I am > > lazy to type. It is necessary to keep habit not to use > > T/F/c/matrix/vector/... as names for objects. So T can be used as > > abbreviation for TRUE like > > > > mean(x, na.rm=T) > > > > as long as you do not define > > > > T<- "Title" > > mean(x, na.rm=T) > > Error in if (na.rm) x<- x[!is.na(x)] : > > argument is not interpretable as logical > > > But note that > > T <- 0 > mean(x, na.rm=T) > > will yield a more surprising result and that's the reason why you really > should not even start to use F and T (neither for a logical value nor > for a number). > > Uwe Ligges I believe that if you consider T/F as reserved word and do not assign number or text to it you can be on safe side. I agree that in programs it is far better to use TRUE/FALSE instead T/F as you never know if user does not define his own T/F (but he can define its own mean function with unexpected result too). There was some thread about T/F and TRUE/FALSE about half a year ago with no definite output, so I consider it probably still quite controversial item. Regards Petr > > > > > > > at least until T/F is removed from such use by R developers > > > > You can even try > > > > ?"T" > > > > and you can read help page for that. > > > > Regards > > Petr > > > > > >> > >> -Peter Ehlers > >> > >> On 2010-06-09 9:08, Larissa Lucena wrote: > >>> Thanks so much!!! I'm using R for the first time, and so, I have many > > stupid > >>> doubts! Sorry and thanks again! > >>> > >>> Regards! > >>> > >>> 2010/6/9 Petr PIKAL<petr.pi...@precheza.cz> > >>> > >>>> Hi > >>>> > >>>> where did you find parameter add=T. > >>>> > >>>> You can use > >>>> > >>>> par(new=T) > >>>> before using new plot command > >>>> > >>>> or use > >>>> > >>>> points, lines > >>>> > >>>> Regards > >>>> Petr > >>>> > > > > ______________________________________________ > > 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.
