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

3 messages · Henrik Bengtsson, Marc Schwartz, Göran Broström

Original
Henrik Bengtsson
# 
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
Marc Schwartz
#
On Jun 20, 2009, at 5:44 PM, Henrik Bengtsson wrote:

            

      
      
      
    

        
Henrik,

Using:

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).


HTH,

Marc Schwartz

  
  


  


      

    

    

      
      

        


  

        

      Göran Broström
    

    

      
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Marc Schwartz wrote:

            

      
      
      
    

        
That is obviously true, but

 > is.integer(1)
 > FALSE


 > is.integer(1:5)
 > TRUE

and, surprisingly,

 > is.integer(1.0:5.2)
 > TRUE

Documentation of ":" says, about 'Value':

"For numeric arguments, a numeric vector.  This will be of type
      'integer' if 'from' and 'to' are both integers and representable
      in the integer type, otherwise of type 'numeric'.

This is true, but not the full truth. Instead it should read

"...This will be of type 'integer' if 'from' is representable in the 
integer type, otherwise of type 'double'"

G?ran