>>>>> "Gabor" == Gabor Grothendieck <[EMAIL PROTECTED]>
>>>>> on Tue, 20 Mar 2007 22:10:27 -0400 writes:
Gabor> On 3/20/07, Duncan Murdoch <[EMAIL PROTECTED]> wrote:
>> On 3/20/2007 1:40 PM, Gabor Grothendieck wrote:
>> > On 3/20/07, Duncan Murdoch <[EMAIL PROTECTED]> wrote:
>> >> On 3/20/2007 12:44 PM, Gabor Grothendieck wrote:
>> >> > On 3/20/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>> >> >> On 3/20/2007 11:19 AM, [EMAIL PROTECTED] wrote:
>> >> >> > Full_Name: Charles Dupont
>> >> >> > Version: 2.4.1
>> >> >> > OS: linux 2.6.18
>> >> >> > Submission from: (NULL) (160.129.129.136)
>> >> >> >
>> >> >> >
>> >> >> > 'format.pval' has a major limitation in its implementation. For
example
>> >> >> > suppose a person had a vector like 'a' and the error being
±0.001.
>> >> >> >
>> >> >> > > a <- c(0.1, 0.3, 0.4, 0.5, 0.3, 0.0001)
>> >> >> > > format.pval(a, eps=0.01)
>> >> >> >
>> >> >> > If that person wants to have the 'format.pval' output with 2
digits always
>> >> >> > showing (like passing nsmall=2 to 'format'). That output would
look like
>> >> >> > this.
>> >> >> >
>> >> >> > [1] "0.10" "0.30" "0.40" "0.50" "0.30" "<0.01"
>> >> >> >
>> >> >> > That output is currently impossible because format.pval can only
>> >> >> > produce output like this.
>> >> >> >
>> >> >> > [1] "0.1" "0.3" "0.4" "0.5" "0.3" "<0.01"
>> >> >> >
>> >> >> >
>> >> >> > ---------------------------------------------------------------
>> >> >> > a <- c(0.1, 0.3, 0.4, 0.5, 0.3, 0.0001)
>> >> >> > format.pval(a, eps=0.01)
>> >> >>
>> >> >> But there's a very easy workaround:
>> >> >>
>> >> >> format.pval(c(0.12, a), eps=0.01)[-1]
>> >> >>
>> >> >> gives you what you want (because the 0.12 forces two decimal place
>> >> >> display on all values, and then the [-1] removes it).
>> >> >>
>> >> >
>> >> > Clever, but the problem would be that summary.lm, etc. call
format.pval so the
>> >> > user does not have a chance to do that.
>> >>
>> >> I don't see how this is relevant. summary.lm doesn't let you pass a
new
>> >> eps value either. Adding an "nsmall=2" argument to format.pval
wouldn't
>> >> help with the display in summary.lm.
>> >>
>> >> I suppose we could track down every use of format.pval in every
function
>> >> in every package and add nsmall and eps as arguments to each of them,
>> >> but that's just ridiculous. People should accept the fact that R
>> >> doesn't produce publication quality text, it just provides you with
ways
>> >> to produce that yourself.
>> >>
>> >> Duncan Murdoch
>> >>
>> >
>> > You are right in terms of my example which was not applicable but I
>> > think in general that format.pval is used from within other routines
rather than
>> > directly by the user so the user may not have a chance to massage it
>> > directly.
>>
>> Right, but this means that it is more or less useless to change the
>> argument list for format.pvals in the way Charles suggested, because all
>> of the existing uses of it would ignore the new parameters.
>>
>> It would not be so difficult to change the behaviour of format.pvals so
>> that for example "digits=2" implied the equivalent of "nsmall=2", but I
>> don't think that's a universally desirable change.
>>
>> The difficulty here is that different people have different tastes for
>> presentation-quality text. Not everyone would agree that the version
>> with trailing zeros is preferable to the one without. R should be
>> flexible enough to allow people to customize their displays, but not
>> necessarily by having every print method flexible enough to satisfy
>> every user: sometimes users need to construct their own output formats.
>>
>> Duncan Murdoch
Gabor> One possibility would be to add args to format.pval whose defaults
Gabor> can be set through options. Not beautiful but it would give the user
Gabor> who really needed it a way to do it.
Yes indeed, I had had the same thought (very early in this
thread). This doesn't mean that I wouldn't agree with Duncan's
statement above anyway.
Whereas I have strong opinion on *not* allowing options() to
influence too many things [it's entirely contrary to the
principle of functional programming],
options() have always been used to tweak print()ing; so they
could be used here as well.
As original author of format.pval(), I'm happy to accept patches
--- if they are done well and also patch
src/library/base/man/format.pval.Rd and ..../man/options.Rd
Martin
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