On Fri, 24 Jun 2005, Vehbi Sinan Tunalioglu wrote:
> Can someone technically explain, why does it take so long with loops in R?
First please demonstrate that it does!
a <- 0
system.time(for(i in 1:1e6) a <- a+1)
takes 1 second for a million iterations and you think that is `so long'?
If you do, the technical explanation is that R is interpreted rather than
compiled.
More likely the problem is *how* you are using loops.
The FAQ mentions reference material on how to use R efficiently and it
would be more productive to learn to do so rather than claim it is
inefficient.
--
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