[R] textConnections so slow!

Prof Brian Ripley ripley at stats.ox.ac.uk
Mon Nov 10 20:45:26 CET 2003


On Mon, 10 Nov 2003, Mathieu Drapeau wrote:

> Is it normal that it takes a very long time to generate a connection 
> object on a big character vector?

Yes.

> This takes a very long time to process:
> lines <- readLines ("myBigFile.txt")
> data <- scan(textConnection(lines), sep = "\t")
> 
> against this that is pretty short to process:
> data <- scan("myBigFile.txt", sep = "\t")
> 
> Anyone has any clues how to efficiently do that because I need to use a 
> textConnection on a big vector?

Why?  There are better ways, even described on the help page!

-- 
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)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595




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