[Rd] Suppressing Scientific Notation
Prof Brian Ripley
ripley at stats.ox.ac.uk
Mon May 5 23:07:14 MEST 2003
I've merged this into R-devel, with some documentation. I couldn't see
a measurable performance change.
On Mon, 5 May 2003, David Brahm wrote:
> Big thanks to Prof Brian Ripley <ripley at stats.ox.ac.uk> and Martin Maechler
> <maechler at stat.math.ethz.ch> for help in building a patch to allow suppression
> of scientific notation! The working patch is attached below. Most helpfully,
> BDR persuaded me to avoid mucking with the options.c code entirely, so I really
> only needed to do three things:
> 1) Add a component "scipen" to the R_print_par_t struct defined in Print.h,
> 2) Set it via GetOption in PrintDefaults, using 0 if the option is undefined,
> 3) Use it in format.c to penalize the character count for scientific notation.
> Normally, R prints "1e+05" rather than "100000" because the former takes only 5
> characters, while the latter takes 6, and 5 < 6. Now if you set
> R> options(scipen=3)
> R will penalize the scientific notation version by 3 characters, and will print
> "100000" in this example because 5+3 >= 6. ("scipen" = "scientific notation
> penalty".) Setting e.g. options(scipen=999) will prevent effectively all
> scientific notation.
> Note I have not documented the new option, and I have not measured how much
> of a performance hit it entails (though I hope the use of PrintDefaults keeps
> that low). Anyway, I submit this patch as a possible future enhancement of R.
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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