Inconsistency in as.data.frame.table for stringsAsFactors
On Fri, Jan 22, 2010 at 2:17 AM, Martin Maechler
<maechler at stat.math.ethz.ch> wrote:
"SM" == Stavros Macrakis <macrakis at alum.mit.edu> ? ? on Thu, 21 Jan 2010 20:19:28 -0500 writes:
? ?SM> I noticed that in as.data.frame.table, the stringsAsFactors argument ? ?SM> defaults to TRUE, whereas in the other as.data.frame methods, it defaults to ? ?SM> default.stringsAsFactors(). ? ?SM> The documentation and implementation agree on this, so this is not a bug. ? ?SM> However, I was wondering if this disparity was intended or if it might be ? ?SM> some sort of unintentional oversight. ?If it is intentional, I wonder what ? ?SM> the rationale is. Some of us (including me) have strongly argued on several occasions that ?global options() settings should *not* have an effect on anything "computing" but just on "output" i.e. printing/graphing of R results. As it is currently, potentially R scripts and R functions may only work correctly for one setting of ? ? options( stringsAsFactors = * ) which is against all principles of functional programming.
A similar argument would also seem to apply to defaultPackages, deparse.max.lines, download.file.method, encoding, expressions, warn and na.action. There are plenty of functions in R that violate other principles of functional programming, so, by itself, this argument seems a little weak to me. There are obviously differences of opinion about this issue in R core, and it's unfortunate that the user has to be exposed to them through inconsistent function definitions. Hadley