[R] read.xport: Writing and reading dataframe to disk directly

From: Anupam Tyagi <AnupTyagi_at_yahoo.com>
Date: Tue 26 Sep 2006 - 16:38:08 GMT


Hi All, is there a way of directly writing to disk file, the dataframe or list of dataframes that result from read.xport function. This function converts SAS export files to R dataframes. I would like to convert a SAS transport file to R, but the resulting R dataframes do not fit in the memory of my computer. Is there way to write the output of this fucntion to disk, perhaps using some pipe or connection facility. Something like,

filexpt.lst <- lookup.xport("file.xpt")
# works very well and returns a list with all kind of information about variable
# name, format, labels, etc.

save(filexpt.df <- read.xport("file.xpt"), file="filexpt.Rdata")
# from what I can tell, this will not work.

? Is there a way to use a pipe or connection to write filexpt.df to disk as it is being created?
? Is there a way to use a connection to an R dataframe on disk, so I can get subsets (rows or colums) from the dataframe on disk, without having to read it into memory?

I will be thankful for your help and suggestions.

Anupam.



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