R help - Jun 2008 - Number of digits in paste funciton

Hi!

Does anyone know hot to set number of digits to be printed in function 
'paste'?

Tine Mla?

For detailed control of such things see ?sprintf and ?formatC 
S?ren
 


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Sendt: 18. juni 2008 10:21
Til: r-help at r-project.org
Emne: [R] Number of digits in paste funciton

Hi!

Does anyone know hot to set number of digits to be printed in function
'paste'?

Tine Mla?

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Tine wrote:
> Hi!
>
> Does anyone know hot to set number of digits to be printed in function
> 'paste'?
>
Basically, you can't, because as.character always uses 15 digits
(chopping trailing zeros).

Instead, use round(), format(), formatC(), etc. Or sprintf()
> paste(format(pi,digits=4),format(exp(1),digits=6), sep="+")
[1] "3.142+2.71828"
> sprintf(fmt="%.4f+%.6f",pi,exp(1))
[1] "3.1416+2.718282"

-- 
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On Wed, 18 Jun 2008, Tine wrote:
> Hi!
>
> Does anyone know hot to set number of digits to be printed in function 
> 'paste'?
paste() does not print, so we can only guess at what you mean.  The help 
says

      'paste' converts its arguments (_via_ 'as.character') to
character
      strings, and concatenates them (separating them by the string
      given by 'sep').

So I guess you are talking about conversion by as.character.  And its help 
says

     'as.character' represents real and complex numbers to 15
      significant digits (technically the compiler's setting of the ISO
      C constant 'DBL_DIG', which will be 15 on machines supporting
      IEC60559 arithmetic according to the C99 standard).  This ensures
      that all the digits in the result will be reliable (and not the
      result of representation error), but does mean that conversion to
      character and back to numeric may change the number.  If you want
      to convert numbers to character with the maximum possible
      precision, use 'format'.

and format() seems to be what you too are looking for (or sprintf or 
formatC).
>
> Tine Mla?
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
PLEASE do at least read the help before posting, as the posting guides 
asks of you.

-- 
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