[R] file reading problem unique to windows. Err info: Error in file(file, ifelse(append, "a", "w")). cannot open the connection

[Prof Brian Ripley]

We don't have any of the information asked for in the posting guide, 
such as your version of R, reproducible example ....

But please try R-patched, since this might be

     • download.file() could leave the destination file open if the URL
       was not able to be opened.  (PR#14414)

(If you had followed the posting guide you would have tried R-patched 
before posting ....)


On Wed, 24 Nov 2010, Yong Wang wrote:

> Dear List
>
> I asked this question before, got some tips but can't get it solved.

Where?  You didn't give a reference, and it would have helped the 
helpers.

> it is clear now that this problem only occurs when run on windows (I
> tested it on windows XP) nothing wrong at all when run on unix.
> unfortunately, sometimes I have to run it on windows,
> I appreciate any suggestion on how to circumvent this problem when run
> on windows.
> below is the problem description I submitted before.
>
> #############################################################
>
> I am running a loop downloading  web pages and save the html to a
> temporary file (use download.file() )
> then read (using readLines)  it in for processing;
> finally write useful info from each processed page to a unique file
>
> the problem is once the loop runs up to somewhere near  5000, it will
> throw out an err like below and won't go further.
>
> ----------------------------------------------------------------
> Error in file(file, ifelse(append, "a", "w")) :
> cannot open the connection
> -----------------------------------------------------------------
>
> In the meantime, a request for new connection won't be successful, for
> example, a request for the help page of "file" will trigger err below
>
> -----------------------------------------------------------------------
> ?file
> Error in gzfile(file, "rb") : cannot open the connection
> In addition: Warning message:
> In gzfile(file, "rb") :
> cannot open compressed file
> 'C:/PROGRA~1/R/R-211~1.1/library/stats/help/aliases.rds', probable
> reason 'Too many open files'
> -----------------------------------------------------------------------
>
> I am not sure if the problem is too many connections not closed. since
> I close the file connection after each readLines.
> checking with showConnections(all=T) does not show excessive
> connections and closeAllConnections() does not help.
>
> Can any one help me on this?
>
>
> Any answer highly appreciated.
>
> yong
>
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> 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