[Rd] signif {base}: changes to scientific notation

Wolfram Fischer - Z/I/M wolfram@fischer-zim.ch
Fri Feb 7 11:14:02 2003


format() did not well the job I wanted.

But I arrived to solve my problem using (e.g.):
	 formatC( signif( 1.234 * 10^(1:8), 3 ), digits=7, flag='-' )


--- In reply to: ---
>Date:    06.02.03 15:53 (+0000)
>From:    ripley@stats.ox.ac.uk
>To:      To Wolfram Fischer - Z/I/M
>Cc:      r-devel@stat.math.ethz.ch
>Subject: Re: [Rd] signif {base}: changes to scientific notation
>
> You are confusing signif() and printing!
> 
> signif() returns a real number.
> 
> Printing does exactly what it is described to do, and has no concept of 
> how the number was produced.
> 
> I guess you were looking for format(), which allows more control.
> 
> On Thu, 6 Feb 2003, Wolfram Fischer - Z/I/M wrote:
> 
> > PROBLEM
> >     `signif' does change to scientic notation
> >     at different levels depending on the number
> >     of significant digits in the input.
> > 
> >     This can generate tables where figures change
> >     ``irregularly'' from normal to scientific notation.
> > 
> > 
> > PROPOSAL
> >     The change to the scientific notation should
> >     be made only if the figure in scientific notation
> >     - with potentially as many significant digits as 
> > 	given as argument to the call of `signif' -
> >     would be shorter than the figure in normal notation.
> 
> This is a misunderstanding of what is happening
> 
> -- 
> Brian D. Ripley,                  ripley@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