Re: [Rd] Inconsistency in as.data.frame.table for stringsAsFactors

From: Martin Maechler <maechler_at_stat.math.ethz.ch>
Date: Fri, 22 Jan 2010 09:17:46 +0100

>>>>> "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.

>From this (my) point of view, we should strive to eventually deprecate
default.stringsAsFactors() which basically returns getOption("stringsAsFactors"), or as first/2nd step redefine it as

 default.stringsAsFactors <- function() TRUE

Martin Mächler.

    SM> Thanks,
    SM> -s



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