R help - Sep 2001 - How to ask smart questions (was RE: [S] A plea (was RE: [S] Diffe rences between UNIX and PC)

For those of you who are interested, here's is the link:
http://www.tuxedo.org/~esr/faqs/smart-questions.html

(Sorry for x-posting...  I thought it is relevant to both lists.)

Andy
> -----Original Message-----
> From: Liaw, Andy [mailto:andy_liaw at merck.com]
> Sent: Thursday, September 27, 2001 4:28 PM
> To: 'Sinclair, Andrew (MIP London)'; 's-news'
> Subject: Re: [S] A plea (was RE: [S] Differences between UNIX and PC
> 
> 
> Couldn't agree more.  I recently heard that Eric Raymond (an 
> Open Source
> advocate) is putting together a web site (?) that tells 
> people how to ask
> questions on the 'Net so as to maximize their chance of getting useful
> answers.  Seems like it would be a good place for some to 
> visit... unless
> they are *not* interested in getting answers, but just wanted 
> to get it off
> their chest...
> 
> Just my $0.02.
> 
> Andy
> 
> > -----Original Message-----
> > From: Sinclair, Andrew (MIP London)
> > [mailto:ASinclair at maninvestmentproducts.com]
> > Sent: Thursday, September 27, 2001 11:18 AM
> > To: 's-news'
> > Subject: [S] A plea (was RE: [S] Differences between UNIX and 
> > PC version
> > of Splus)
> > 
> > 
> > I just want to make a brief plea for people posting queries 
> > to s-news to 
> > include code fragments that can actually be run and demonstrate the 
> > problem or error that they are referring to.  This makes it 
> > much easier
> > for respondents to give useful answers and saves a lot of 
> time for all
> > concerned.
> > 
> > For example it seems to me that most of the disagreements 
> > in the diatribe below could more easily have been cleared up if   
> > there were specific code fragments to discuss.  I am sure 
> > neither David Smith nor Sicco Schets is a liar.  Either Sicco
> > has a bug in his code or he has uncovered a bug/inconsistency in 
> > some version of Splus or he has misunderstood the results he is 
> > getting.  My point is that noone can tell because we can only
> > speculate about the exact situation in which he observed the
> > behaviour he mentions.  
> > 
> > I do not intend to imply any criticism to either party in 
> > this discussion.
> > Just a (hopefully) constructive comment about the usage of s-news.
> > 
> > Kind regards,
> > 
> > Andrew
> > 
> > 
> > 
> > >-----Original Message-----
> > >From: Sicco Schets [mailto:Sicco.Schets at asml.com]
> > >Sent: Thursday, September 27, 2001 10:32 AM
> > >To: David Smith
> > >Cc: s-news at wubios.wustl.edu
> > >Subject: Re: [S] Differences between UNIX and PC version of Splus
> > >
> > >
> > >Hi,
> > >
> > >Firstly, I want to mention that my first mail was not so much 
> > >intended for
> > >people to solve the problem examples that I have. It was more 
> > >just to get
> > >things of my chest about Splus. Of couse, I also hoped that 
> > >someone could point
> > >me in the direction where I can learn more about modes, 
> > >coercion and the like,
> > >because I still like to believe that the 
> > >errors/bugs/issues/features that I
> > >observe are due to my own lack of this undersanding.
> > >
> > >Furthermore, see my comments between the lines below.
> > >
> > >David Smith wrote:
> > >
> > >> Sicco Schets reports problems transferring functions between 
> > >two versions of
> > >> S-PLUS, which turn out to be from S-PLUS 6 to S-PLUS 2000.  
> > >Although this is
> > >> somewhat to be expected due to the very different versions, 
> > >the problems he
> > >> reports are really just "features" of the language.
> Details below.
> > >>
> > >> > The PC trial version I was testing on is Splus-2000 
> Release 3 for
> > >> > Windows.
> > >>
> > >> In that case, you were tranferring code unaltered from 
> > >S-PLUS 6 for Unix to
> > >> S-PLUS 2000 Windows, a version of S-PLUS more than 18 months 
> > >older and based
> > >> on an entirely different language engine.
> > >
> > >Actually I was porint code that worked on the PC version to 
> > >the UNIX version 6.
> > >
> > >But I feel that the 'older' Windows version deals better
with
> > >these problems.
> > >
> > >> S-PLUS is largely
> > >> backwards-compatibility, but (lacking the gift of 
> > >prescience) we do not
> > >> claim such levels of forwards-compatibility.  Had you moved 
> > >code between
> > >> S-PLUS 6 for Unix and S-PLUS 6 for Windows I'd have 
> > expected no such
> > >> problems.  We provide tools for moving code between S-PLUS 
> > >2000 for Windows
> > >> and S-PLUS 6 for Windows, and also between S-PLUS 3.4 for 
> > >Unix and S-PLUS
> > >> 5/6 for Unix, but not in the reverse direction.
> > >>
> > >> > if (reg expr)
> > >> > {
> > >> >  code
> > >> > }
> > >> > else
> > >> > {
> > >> >     code
> > >> > }
> > >> >
> > >> > doesn't work
> > >>
> > >> I agree this could be considered a bug, but this kind of 
> > >thing happens with
> > >> all interpreted languages.
> > >
> > >I agree, but why is this behavior not consistent? It is not 
> > >always that the
> > >above code doesn't work!! PC version has no problems with it.
> > >
> > >> Scripts are processed line-by-line, and if a
> > >> line forms the end of a complete expression, the expression 
> > >is evaluated.
> > >> else clauses aren't the only instance of this:
> > >>
> > >>         x <- 10
> > >>         -y
> > >>
> > >> Should this be interpreted as "x <- 10-y", or as
two
> > >separate expressions?
> > >> The rule of stopping at complete expressions is sometimes 
> > >inconvenient, but
> > >> not having it can introduce much worse ambiguities.  (You 
> > >might think that
> > >> when reading from script files, looking ahead to the next 
> > >line could resolve
> > >> ambiguities, as in the if/else case.  But then, pasting text 
> > >to the command
> > >> line as opposed to using source() could have different 
> > >results. That's bad
> > >> too.)
> > >>
> > >> In any case, this issue exists in both S-PLUS 2000 and 
> > >S-PLUS 6, so at least
> > >> it's backwards (and forwards!) compatible.
> > >
> > >Not true!
> > >
> > >>
> > >>
> > >> > Or the mode of e.g a data.frame is returned by a
function
> > >> > differently on the 2 platforms.
> > >>
> > >> I don't believe this is true.  There are several classes 
> > >where the *class*
> > >> of an object will be different in S-PLUS 6 than S-PLUS 2000 
> > >(basic objects
> > >> like vectors and matrices come to mind), but the behaviour 
> > >of mode() hasn't
> > >> changed.
> > >
> > >Well, I'm not sucking this out of my thumb. I see this 
> > >phenomenon. I know the
> > >reason for it may be something else than the behavior of 
> > mode() between
> > >platforms. I am trying to understand what causes this. I don't
> > >need anyone
> > >telling me that it is not true.
> > >
> > >
> > >>
> > >>
> > >> > And if I have a statement like 'return(list(a=bla,
b=blabla)'
> > >> > inside a 'tapply' then on the PC version I can 
> reference the vars
> > >> > with $a and $b. However, on the UNIX version I
can't.
> > >>
> > >> I don't believe this to be true either (although it's
hard
> > >to tell exactly
> > >> what you mean).
> > >
> > >OK I'm just stirring some BS. Nevertheless I have observed 
> > >this and solved it
> > >by using the [[ ]] notation.
> > >
> > >>
> > >>
> > >> > Another issue is that you can have a data.frame (made
with
> > >> > read.table()) with
> > >> > a column of doubles. If you ask for the mode of this
column it
> > >> > will tell you
> > >> > it's numeric, but if you then multiply this column
with any
> > >> > number you get an
> > >> > error stating that multiplication cannot be done on
factors.
> > >>
> > >> This behaviour exists in all versions of S-PLUS (since 
> > >version 3, at least).
> > >> Like many aspects of the S language, the behaviour of 
> > >factors is undoubtedly
> > >> quirky, but it is consistent. In S-PLUS 6 you can turn off 
> > >automatic factor
> > >> coercieon with the options(stringsAsFactors=F).  If your 
> > >column really was
> > >> doubles, there must have been a text character there 
> > >sometime for it to have
> > >> been converted to a factor.
> > >
> > >Well no, the whole column is in the scientific notation, with 
> > >a possible NA
> > >somewhere. So, it could be that an NA is read by read.table() 
> > >as a character,
> > >explaining this, but that is, in my opinion, not the desired 
> > >behavior. If Splus
> > >supports NA, which is great,  it should support it everywhere.
> > >
> > >thanks
> > >Sicco
> > 
> > 
> > 
> > 
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