[R] Replies on this list [was: removing NA from a data frame]
ligges at statistik.uni-dortmund.de
Tue Mar 21 13:59:40 CET 2006
François Pinard wrote:
> [Berton Gunter]
>>>PPS. how do I figure out the number of rows in a data.frame?
>>> is length(attr(X,"row.names")) the right way?
>>help.search("number of rows") immediately gets you your answer!
> Hi, people. Here, I get:
> Help files with alias or concept or title matching ‘number of rows’
> using fuzzy matching:
> nrow(base) The Number of Rows/Columns of an Array
> and '?nrow' says that it meant for arrays: nothing about data.frame, and
Very well about data.frames! ?nrow says in its argument description:
"x a vector, array or data frame "
> not a generic method either. Even if it was a class method, we should
> not expect a new user to be very familiar with R (both!) class systems
> from the start.
> What a new user might think, reading the documentation? Sam Steingold
> is surely an experimented and competent computer guy. He might guess,
> who knows, that some automatic array to data.frame conversion occurs
> (all inefficient that it could be). Yet this would not match other
> knowledge nor experimentation, as a data.frame is hardly an array:
> > x = data.frame(a=1:3, b=c(TRUE, TRUE, FALSE), c=letters[1:3])
> > as.array(x)
> Erreur dans "dimnames<-.data.frame"(`*tmp*`, value = list(c("a", "b", "c" :
> 'dimnames' incorrect pour ce tableau de données
> Despite help.search("number of rows") provides an answer that happens to
> be right, it might not be recognised as such by an intelligent reader,
> and so, it is not really satisfactory. The documentation for "nrow"
> could be improved by saying that it applies to any kind of structure for
> which dim() is meaningful. And even then, ?dim is silent about data
> frames. One clue (yet a pretty weak one) that nrow may be applied to
> a data.frame comes from the fact that ?dim.data.frame lists the same
> documentation as ?dim.
> Why do I say all this? Because it happens, not necessarily in this
> case, a bit too often nevertheless, that answers given to users are
> uselessly harsh or haughty. Especially when they imply that the
> documentation is perfect. One problem is that some people enjoy reading
> such replies. As example of this strange kind of pleasure, here is
> a excerpt from R Archives, which I find especially enlightening on the
> mentality of few members:
> From: swis at mantrade.com (Steve Wisdom)
> Date: 2003-12-26 17:04
> Subject: [R] re| Dr Ward on List protocol
> "Andrew C. Ward" <acward at uqconnect.net.au> :
> >With respect to 'tone' and 'friendliness', perhaps all that is meant or
> >needed is that people be polite and respectful.
> >I shake my head as often at rude answers
> Oh, by gosh, by golly.
> I don't think an occasional dose of 'real life', via a jab from the
> Professor, will cause any lasting harm to the cosseted & emolumated students
> and academics on the List.
> On a Wall St trading desk, for example, every day one is kicked in the head
> more brutally by clients, superiors, counterparts, the markets & etc, than
> ever one would be by the Professor.
> Plus, the Professor's jabs are good Schadenfreudic fun for the rest of us.
> Steve Wisdom
> Westport CT US
> The truth is that not everybody around here is "cosseted & emolumated
> students and academics". Moreover, behaviour at trading desks is fully
> irrelevant, and for most of us, this is not the kind of life we chose to
> live. Wrong behaviour elsewhere is hardly an excuse for not behaving
> properly, here.
> Moreover, what is mere "good fun" for some may be perceived as highly
> inelegant by others. While some competent members may inspire
> admiration and charism by their knowledge and dedication, they sometimes
> damage beyond repair what they inspire, when showing poor humanity.
> I'm aware of the constant fear some have of seeing this list abused.
> There are ways for not being abused, which do not require becoming
> abusive ourselves. We should deepen such ways in our own habits.
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