[Rd] format.factor (PR#11512)

[oehl_list at gmx.de]

Dear all,

differing from the standard behaviour of 'format' the current (2.7.0) 'format.factor' destroys attributes like 'dim' and 'dimnames'. This unfortunately breaks some general code in the new package 'ff' for large file-based data which will support vectors and arrays of atomic and factors. 

It would be nice if you could include the following fix in the next release of R. 

Kind regards

Jens Oehlschlägel

format.factor <-
function (x, ...){
  a <- attributes(x)
  a$class <- NULL
  a$levels <- NULL
  x <- as.character(x)
  attributes(x) <- a
  format(x, ...)
}


>   x <- factor(c("aa",letters[-1]))
>   dim(x) <- c(13,2)
>   format(x, justify="right")
 [1] "aa" " b" " c" " d" " e" " f" " g" " h" " i" " j" " k" " l" " m" " n" " o" " p" " q" " r" " s" " t" " u" " v" " w" " x" " y" " z"
> 
>   format.factor <-
+   function (x, ...){
+     a <- attributes(x)
+     a$class <- NULL
+     a$levels <- NULL
+     x <- as.character(x)
+     attributes(x) <- a
+     format(x, ...)
+   }
> 
>   format(x, justify="right")
      [,1] [,2]
 [1,] "aa" " n"
 [2,] " b" " o"
 [3,] " c" " p"
 [4,] " d" " q"
 [5,] " e" " r"
 [6,] " f" " s"
 [7,] " g" " t"
 [8,] " h" " u"
 [9,] " i" " v"
[10,] " j" " w"
[11,] " k" " x"
[12,] " l" " y"
[13,] " m" " z"

> version
               _                           
platform       i386-pc-mingw32             
arch           i386                        
os             mingw32                     
system         i386, mingw32               
status                                     
major          2                           
minor          7.0                         
year           2008                        
month          04                          
day            22                          
svn rev        45424                       
language       R                           
version.string R version 2.7.0 (2008-04-22)

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