[R] Considering port of SAS application to R

[Philippe Grosjean]

Please, read the R Data Import/Export manual provided with any version 
of R, and come back with more specific questions.

In general, R cannot deal with datasets as large as those handled by 
SAS. But this is true only when you use standard R functions, like 
read.table(), which are not written to save memory and load very large 
datasets (other aspects are optimized).

I would advise to put your data in a database and then access to it 
piece-by-piece using SQL queries. There are very little cases where you 
actually need the whole dataset in memory at once. A simple database 
system, if you just need to access those data (no complex database 
operations required) is SQLite. There is an R package to connect to such 
a database without extra software needed. Thus, very convenient.

Best,

Philippe Grosjean

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  ) ) ) ) )
( ( ( ( (    Prof. Philippe Grosjean
  ) ) ) ) )
( ( ( ( (    Numerical Ecology of Aquatic Systems
  ) ) ) ) )   Mons-Hainaut University, Belgium
( ( ( ( (
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Werner Wernersen wrote:
> Hi there!
> 
> I am considering to port a SAS application to R and I would like to hear your opinion if you think this is possible and worthwhile. SAS is mainly used to do data management and then to do some aggregations and simple computations on the data and to output a modified data set. The main problem I see is the size of the data file. As I have no access to SAS yet I cannot give real details but the SAS data file is about 7 gigabytes large. (It's only the basic SAS system without any additional modules)
> 
> What do you think, would a port to R be possible with reasonable effort? Is R able to handle that size of data? Or is R prepared to work together with some database system?
> 
> Thanks for your thoughts!
> 
> Best regards,
>   Werner
> 
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