[R] How to add a new plot in the same graph using add=T at the command plot?

[Petr PIKAL]

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.