[R] memory cleaning

[Prof Brian Ripley]

See help("gc") and read up about garbage collection.  Memory measurements 
without a preceding gc() are meaningless.

You have not told us your version of R, but 2.1.0 and later do use much 
less memory in write.table.  Nevertheless, they do have to convert each 
column to character and that does take some memory.

On Fri, 22 Jul 2005, Claude  Messiaen - Urc Necker wrote:

> Hi R Users,
> After some research I haven't find what I want.
> I'm manipulating a dataframe with 70k rows and 30 variables, and I run out of memory when exporting this in a *.txt file
>
> after some computing I have used :
>
>> memory.size()/1048576.0
> [1] 103.7730
>
> and I make my export :
>
>>  write.table(cox,"d:/tablefinal2.txt",row.names=F,sep=';')
>>  memory.size()/1048576.0
> [1] 241.9730
>
> I'm surprised so I try removing some objects :
>>  rm (trait,tany,tnor,toth,suivauxdany,dnor,doth,mod1,
> mod2,mod3,lok1,lok2,lok3,aux,risque,risk)
> and check memory space :
>> memory.size()/1048576.0
> [1] 242.1095
>
> First, I don't understand why when removing objects the memory used increase ?
> Next, why the memory used double when I make an export ?
> I look forward to your reply
>
> Claude
>
> 	[[alternative HTML version deleted]]
>
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-- 
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)
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