On 04/01/2012 17:12, William Dunlap wrote:
Re
   >  How can I avoid the warning message altogether?

   ?closeAllConnections

I think of calls to closeAllConnections() in the same
way that I think of calls to rm(list=objects()):
they both can remove things that are not theirs to remove.

Calling gc() will close all unused connections, so
no damage can be done.  (I thought that the warning
about closing unused text connections was dropped in
a recent release of R so neither is really needed.)

Yes, it was. The warning is there because the user may need to do something about the 'other end' of the now-closed connection, which R manages for textConnections.

There is however one circumstance where gc() does not close all unused connections, and that is when gzcon() is used (because that involves two connections and it is not clear when the inner one is 'in use': and we used to guess wrong).

Rather than using a sledgehammer, use showConnections(all=TRUE) to see all connections, and close the ones you want to (and its help page shows you how).

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com

-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On 
Behalf Of David Winsemius
Sent: Wednesday, January 04, 2012 7:10 AM
To: Dan Abner
Cc: r-help@r-project.org
Subject: Re: [R] Warning message about closing a connection XXXX


On Jan 4, 2012, at 9:53 AM, Dan Abner wrote:

Hello everyone,

After running the following code, I obtain this error message.


mydata<- read.table(textConnection(mystring),
+    header=TRUE, sep=",",
+    row.names="id", na.strings=" ")
mydata
Warning message:
closing unused connection 3 (mystring)

=====

However, when I attempt to run read.table() again and immediately
submit
the close() function (below), I obtain this message:

close(mystring)
Error in UseMethod("close") :
  no applicable method for 'close' applied to an object of class
"character"
=====

How can I avoid the warning message altogether?

?closeAllConnections

The error message occurs because "mystring was never the connection
name.

--

David Winsemius, MD
West Hartford, CT

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--
Brian D. Ripley,                  rip...@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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