[R] R-level expansion of Rplot%03d.png
Prof Brian Ripley
ripley at stats.ox.ac.uk
Sat Aug 21 18:27:57 CEST 2010
Just so this thread is complete on the record:
Filenames such as "Rplot%03d.png" are used in C code as format strings
when opening a file. Nothing in R subsequently knows the file name --
the file is accessed through the FILE* pointer.
Despite what baptiste 'assumes', it is clearly documented that the
string is used to format the *page number*: there is no regex search.
E.g. (?png, Unix)
filename: the name of the output file. The page number is substituted
if a C integer format is included in the character string, as
in the default.
There is no API to find the current page number, nor AFAIR in all the
years of the R graphics device API has anyone asked for one.
If I wanted to do anything like this I would expect to generate
filenames myself and open a new png() device for each plot. But the
alternative is to count the number of pages your code generates (which
may need detailed knowledge of what the plot commands do).
On Sat, 21 Aug 2010, kees duineveld wrote:
> You are correct. (I really should start using these reading glasses).
>
> My apologies
>
> On Sat, 21 Aug 2010 14:20:17 +0200, baptiste auguie
> <baptiste.auguie at googlemail.com> wrote:
>
>> I dunno, it doesn't seem to do it for me,
>>
>> name = "Rplot%03d.png"
>> real.name = path.expand(name)
>> real.name
>> #[1] "Rplot%03d.png"
>> list.files(patt=".png")
>> #[1] "Rplot001.png"
>>
>> sessionInfo()
>> R version 2.11.1 (2010-05-31)
>> i386-apple-darwin9.8.0
>>
>> locale:
>> [1] en_GB.UTF-8/en_GB.UTF-8/C/C/en_GB.UTF-8/en_GB.UTF-8
>>
>> attached base packages:
>> [1] stats graphics grDevices utils datasets methods base
>>
>>
>>
>> On 21 August 2010 14:15, kees duineveld <kees.duineveld at gmail.com> wrote:
>>> Now I understand. You need the name which png() does not return.
>>> So I think you need to do (untested, I am struggling with the cat()):
>>>
>>>
>>> makePlot = function(p, name="Rplot%03d", width=300)
>>> {
>>> real.name.png = path.expand(paste(name,'.png'sep='') # function needed
>>> here
>>> real.name.pdf = path.expand(paste(name,'.pdf'sep='') # function needed
>>> here
>>> png(real.name.png)
>>> print(p)
>>> dev.off()
>>> pdf(real.name.pdf)
>>> print(p)
>>> dev.off()
>>> cat(noquote(paste('image:',real.name.png,',width=',width,',link=real.name.pdf)
>>> }
>>>
>>> On Sat, 21 Aug 2010 14:02:04 +0200, baptiste auguie
>>> <baptiste.auguie at googlemail.com> wrote:
>>>
>>>> My function needs to do two things with the filename:
>>>>
>>>> First, create the plot file. For this, Rplot%03d is OK because it is
>>>> correctly interpreted by the graphics device.
>>>>
>>>> Second, generate a text string referring to this filename. This is
>>>> where I need to convert Rplot%03d to, say, Rplot001. I am assuming
>>>> that it is implemented internally by looking at the files in the
>>>> current directory with some regular expression search, and
>>>> incrementing the end number as needed. I wonder if there's a high
>>>> level function to perform this task.
>>>>
>>>> Best,
>>>>
>>>> baptiste
>>>>
>>>> On 21 August 2010 13:35, kees duineveld <kees.duineveld at gmail.com> wrote:
>>>>>
>>>>> Not sure what you want. Plot does that automatically. It seems to use
>>>>> path.expand() to make the %03d expansion. Not that path.expand() is
>>>>> documented to do this, but it seem to work.
>>>>>
>>>>> Kees
>>>>>
>>>>> On Sat, 21 Aug 2010 13:04:54 +0200, baptiste auguie
>>>>> <baptiste.auguie at googlemail.com> wrote:
>>>>>
>>>>>> Dear list,
>>>>>>
>>>>>> I'm using the brew package to generate a report containing various
>>>>>> plots. I wrote a function that creates a plot in png and pdf formats,
>>>>>> and outputs a suitable text string to insert the file in the final
>>>>>> document using the asciidoc syntax,
>>>>>>
>>>>>> <%
>>>>>> tmp <- 1
>>>>>> makePlot = function(p, name=paste("tmp",tmp,sep=""), width=300)
>>>>>> {
>>>>>> png(paste(name,".png",sep=""))
>>>>>> print(p)
>>>>>> dev.off()
>>>>>> pdf(paste(name,".pdf",sep=""))
>>>>>> print(p)
>>>>>> dev.off()
>>>>>>
>>>>>>
>>>>>> cat(noquote(paste('image:',name,'.png["',name,'",width=',width,',link="',name,'.pdf"]',sep="")))
>>>>>> tmp <<- tmp + 1
>>>>>> }
>>>>>> %>
>>>>>>
>>>>>> The resulting html file contains a thumbnail of the png file, with a
>>>>>> link to the pdf file.
>>>>>>
>>>>>> I'm not happy with my default filename for the graphics. Is there a
>>>>>> way to expand the default filename of R graphic devices? I would like
>>>>>> to call it like this,
>>>>>>
>>>>>>
>>>>>> makePlot = function(p, name="Rplot%03d", width=300)
>>>>>> {
>>>>>>
>>>>>> real.name = expandName(name) # function needed here
>>>>>> png(paste(name,".png",sep=""))
>>>>>> print(p)
>>>>>> dev.off()
>>>>>> pdf(paste(name,".pdf",sep=""))
>>>>>> print(p)
>>>>>> dev.off()
>>>>>>
>>>>>>
>>>>>> cat(noquote(paste('image:',real.name,'.png["',real.name,'",width=',width,',link="',real.name,'.pdf"]',sep="")))
>>>>>> }
>>>>>>
>>>>>>
>>>>>> Sincerely,
>>>>>>
>>>>>> baptiste
>>>>>>
>>>>>> ______________________________________________
>>>>>> 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.
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> ______________________________________________
>>>>> 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.
>>>>>
>>>
>>>
>>> --
>>> Using Opera's revolutionary email client: http://www.opera.com/mail/
>>>
>
>
> --
>
> ______________________________________________
> 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.
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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