R help - Jan 2011 - RData size

Hi, I noticed a Rdata size issue that's puzzling to me. Attached find 2
example
datasets in text file. Both are 100x5, so the sizes for both text file are the 
same. However, when I read them into R, the sizes are much different:

tt<-as.matrix(read.table("tt.txt",header=T,row.names=1))
save(tt,file='tt.RData')

tt.big<-as.matrix(read.table("tt.big.txt",header=T,row.names=1))
save(tt.big,file='tt.big.RData')

"tt.RData" is 2KB while "tt.big.RData" is 5KB. This is not a
big deal with the
example datasets, but my real datasets are much larger, the difference is 35MB 
vs. 1MB for the RData objects. 


The difference between the 2 datasets above is that "tt.big" is a
smoothed
version of "tt", so there are a lot less unique values in tt.big than
tt, I
guess this is the reason for the difference in sizes of RData objects, can 
anyone confirm? 


Thanks

John


      
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You can confirm it very easy by adding 'compress = FALSE' to the save
function.  You will see that the .RData files are the same size since
you are not compressing them.

On Tue, Jan 4, 2011 at 7:19 PM, array chip <arrayprofile at yahoo.com>
wrote:
> Hi, I noticed a Rdata size issue that's puzzling to me. Attached find 2
example
> datasets in text file. Both are 100x5, so the sizes for both text file are
the
> same. However, when I read them into R, the sizes are much different:
>
> tt<-as.matrix(read.table("tt.txt",header=T,row.names=1))
> save(tt,file='tt.RData')
>
>
tt.big<-as.matrix(read.table("tt.big.txt",header=T,row.names=1))
> save(tt.big,file='tt.big.RData')
>
> "tt.RData" is 2KB while "tt.big.RData" is 5KB. This is
not a big deal with the
> example datasets, but my real datasets are much larger, the difference is
35MB
> vs. 1MB for the RData objects.
>
>
> The difference between the 2 datasets above is that "tt.big" is a
smoothed
> version of "tt", so there are a lot less unique values in tt.big
than tt, I
> guess this is the reason for the difference in sizes of RData objects, can
> anyone confirm?
>
>
> Thanks
>
> John
>
>
>
> ______________________________________________
> 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.
>
>


-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?