From: Petr PIKAL <petr.pikal_at_precheza.cz>

Date: Thu, 10 Jun 2010 11:15:50 +0200

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. Received on Thu 10 Jun 2010 - 09:18:54 GMT

Date: Thu, 10 Jun 2010 11:15:50 +0200

Hi

Uwe Ligges <ligges_at_statistik.tu-dortmund.de> napsal dne 10.06.2010 10:37:05:

*>
**>
*

> On 10.06.2010 10:19, Petr PIKAL wrote:

*> > Hi
**> >
**> > Peter Ehlers<ehlers_at_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.pikal_at_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_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.

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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. Received on Thu 10 Jun 2010 - 09:18:54 GMT

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