[R] How to comment in R
(Ted Harding)
Ted.Harding at manchester.ac.uk
Wed Feb 11 11:50:59 CET 2009
To expand on Søren's comment (and hopefully help to clarify things):
[1]
The R *language* sees "#", and nothing else, as the start of a comment.
A comment continues from the initial "#" until the end of the line
on which that occurs, and no further. (Any number of "#" may be
included in a comment, of course).
You cannot fool the R interpreter into ignoring the end-of-line by
putting "\" at the end of the line (this works with some software,
but not with R).
[2]
tinn-R is an editor, whose output is R code for submission to the
R language interpreter. It cannot change how the R language interpreter
recognises a comment line (that is always as in [1]).
[3]
The suggestion often made for "commenting out blocks of code",
to wrap them in
if(FALSE){
<block of code>
}
works *only* if <block of code> is syntactically correct R code.
The R interpreter does not think "Ah, 'if(FALSE)' is never satisfied,
so I don't need to look at what's in '{...}'." It always looks!
So you are back to [1]: 1 or more "#" at the start of a comment,
which continues until the end of the line. If a comment extends
over several lines, each one needs a "#". However, as has been
suggested, various text editors make it easier to do that. For
example, in 'vim':
1: Type in the several lines of comment (without "#"). Press 'Esc'.
2. With the cursor in the first line, press 'Shift'+'V'.
3. Move the cursor down to the last line, thus highlighting all.
4. Then type
:s/^/# /
and each line will then start with "# ". (It's very quick once
you are used to it).
Ted.
On 11-Feb-09 10:03:10, Søren Højsgaard wrote:
> You CAN NOT use /* and */ for begin/end comment in R.
>
> But if you choose Options -> Main -> Application in Tinn-R you can
> specify whether you want a comment to start with # or ## or ### or ...
>
> S
>
> ________________________________
>
> Fra: Mihai.Mirauta at bafin.de [mailto:Mihai.Mirauta at bafin.de]
> Sendt: on 11-02-2009 10:54
> Til: Thierry.ONKELINX at inbo.be; Søren Højsgaard; r-help at r-project.org
> Emne: AW: [R] How to comment in R
>
>
>
> Still doesn't work. I did
> Format --> Block --> Comment and chose /* for begin comment,
> */ for end comment
> but R doesn't recognize the signs as such. Maybe I should work on the
> configuration of TINN R?
>
> Thanks,
>
> Mihai
> -----Ursprüngliche Nachricht-----
> Von: ONKELINX, Thierry [mailto:Thierry.ONKELINX at inbo.be]
> Gesendet: Mittwoch, 11. Februar 2009 09:55
> An: Mirauta, Mihai; Soren.Hojsgaard at agrsci.dk; r-help at r-project.org
> Betreff: RE: [R] How to comment in R
>
> Via the menu choose: Format --> Block --> Comment Or use the shortcut
> key alt+C
>
> HTH,
>
> 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 Thierry.Onkelinx at inbo.be
> www.inbo.be
>
> To call in the statistician after the experiment is done may be no more
> than asking him to perform a post-mortem examination: he may be able to
> say what the experiment died of.
> ~ Sir Ronald Aylmer Fisher
>
> The plural of anecdote is not data.
> ~ Roger Brinner
>
> The combination of some data and an aching desire for an answer does
> not ensure that a reasonable answer can be extracted from a given body
> of data.
> ~ John Tukey
>
> -----Oorspronkelijk bericht-----
> Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> Namens Mihai.Mirauta at bafin.de
> Verzonden: woensdag 11 februari 2009 9:47
> Aan: Soren.Hojsgaard at agrsci.dk; r-help at r-project.org
> Onderwerp: Re: [R] How to comment in R
>
> I am using Tinn-R.
>
> -----Ursprüngliche Nachricht-----
> Von: Søren Højsgaard [mailto:Soren.Hojsgaard at agrsci.dk]
> Gesendet: Mittwoch, 11. Februar 2009 09:40
> An: Mirauta, Mihai; r-help at r-project.org
> Betreff: SV: [R] How to comment in R
>
> A hash (#) anywhere on a line will comment out the rest of the line.
> Try!
>
> I don't think there is anything in R that will indicate the beginning
> and end of a "comment section" (like /* .... */ would in SAS). However
> most editors (and certainly emacs and Tinn-R) will allow you to comment
> out several lines.
>
> Søren
>
> ________________________________
>
> Fra: r-help-bounces at r-project.org på vegne af Mihai.Mirauta at bafin.de
> Sendt: on 11-02-2009 09:32
> Til: r-help at r-project.org
> Emne: [R] How to comment in R
>
>
>
>
> Hi everybody,
>
> I use for the moment "#" at the begining of each line for comments.
>
> Is there any possibility to comment more than one line, like something
> which shows the beggingng and the end of the comment? Or is there a
> possibility to comment only a part of a line?
>
> Thanks,
>
> Mihai
>
>
> [[alternative HTML version deleted]]
>
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>
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> PLEASE do read the posting guide
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E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
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Date: 11-Feb-09 Time: 10:50:56
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