From: Uwe Ligges <ligges_at_statistik.tu-dortmund.de>

Date: Thu, 10 Jun 2010 12:30:00 +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 - 10:32:47 GMT

Date: Thu, 10 Jun 2010 12:30:00 +0200

On 10.06.2010 11:15, Petr PIKAL wrote:

*> Hi
**>
*

> Uwe Ligges<ligges@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.
*

At least not controversial for me. ;-)

Uwe

*> 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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