[Rd] Flag '#' in sprintf() format string "%#x"?

Marc Schwartz marc_schwartz at me.com
Sun Jun 21 01:27:45 CEST 2009

On Jun 20, 2009, at 5:44 PM, Henrik Bengtsson wrote:

> Hi, this is a bit of FYI, but also a question.
> Is flag '#' in sprintf() format string "%#x" fully supported across
> platforms?  Can that be assumed?  I discovered thanks to the r-forge
> service, that this was not the case for OSX with "R version 2.9.0
> Under development (unstable) (2009-01-13 r47593)", where R CMD check
> reports the following:
> Error in sprintf("%#x", values) :
>  use format %d, %i, %x or %X for integer objects
> where values <- as.integer(1:5). Note it works well on other
> platforms; I don't know about newer R version on OSX.   Should I
> consider this a glitch in an old version of R (newer R version do a
> much better validation here), or should I simply avoid '#'?
> Thanks,
> /Henrik



R version 2.9.0 Patched (2009-06-05 r48712)

on a fully updated OSX 10.5.7 MacBook Pro:

values <- 1:5

 > sprintf("%#x", values)
[1] "0x1" "0x2" "0x3" "0x4" "0x5"

Note that the as.integer() is not needed, as ':' will return integers  
if both from and to values are integers:

 > str(values)
  int [1:5] 1 2 3 4 5

The only comment that I see in NEWS that may be relevant here for  
2.9.0 is:

     o	sprintf() does stricter error checking on input formats to
	avoid passing invalid formats to the OS (which have a tendency
	to crash under such inputs).


Marc Schwartz

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