R devel - Jul 2012 - print.data.frame function with option na.print=" " actually prints NA

Dear R developers

I thought I better report this behavior.

Example:
> print(matrix(c(1,NA,1,1),2,2), na.print="")
     [,1] [,2]
[1,]    1    1
[2,]         1
> print(as.data.frame(matrix(c(1,NA,1,1),2,2)), na.print="")
  V1 V2
1  1  1
2 NA  1


The help-file for print.data.frame gives me the impression that it should be
possible to specify the na.print option (na.print option works in print.default,
and following the reference to the helpfile for the format function then default
value of na.encode in that function is TRUE).

When I study the code for print.data.frame is see that  format.data.frame is
used with option na.encode = FALSE. Is that the cause for the behavior I see ?
If so, are there good reasons for having it this way ?



Best
Ole Christensen

	[[alternative HTML version deleted]]