[R] scan question

[Peter Dalgaard BSA]

John Logsdon <j.logsdon at lancaster.ac.uk> writes:

> Hi
> 
> In R 0.90.1 is there a way of stopping scan() from rewinding to the
> beginning of the file?  Basically I have a mega-file (250Mb!!!) that I
> want to read and process in 301 line chunks, each line having 151 numbers
> on it.
> 
> If I do
> for (i in 1:many){
>   pp<-scan('filename',skip=(i-1)*301,nlines=301)
> }
> 
> it appears to do what I want but as the chunks get further down the file
> it gets slower and slower.
> 
> So can I stop the rewind?

I don't think you can - until someone implements "connections"
(wazzattherightname?) in R. If you're on some kind of Unix, you may
get away with hacking up something with named pipes.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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