Dear John,fully agreed! In the global environment I always keep my "data-variables" in a data.frame. However, if I look in help I like examples that start with the particular aspects of a function. It is important to know, if a function offers a data argument, but in the first line I don't need an example for the use of a data argument each time I look in help.
best, Heinz Fox, John wrote/hat geschrieben on/am 17.12.2018 16:23:
Dear Heinz, ----------------------------------------------On Dec 17, 2018, at 10:19 AM, Heinz Tuechler <tuech...@gmx.at> wrote: Dear All, do you think that use of a data argument is best practice in the example below?No, but it is *normally* or *usually* the best option, in my opinion. Best, Johnregards, Heinz ### trivial example plotwithline <- function(x, y) { plot(x, y) abline(lm(y~x)) ## data argument? } set.seed(25) df0 <- data.frame(x=rnorm(20), y=rnorm(20)) plotwithline(df0[['x']], df0[['y']]) Fox, John wrote/hat geschrieben on/am 17.12.2018 15:21:Dear Martin, I think that everyone agrees that it’s generally preferable to use the data argument to lm() and I have nothing significant to add to the substance of the discussion, but I think that it’s a mistake not to add to the current examples, for the following reasons: (1) Relegating examples using the data argument to “see also” doesn’t suggest that using the argument is a best practice. Most users won’t bother to click the links. (2) In my opinion, an new initial example using the data argument would more clearly suggest that this is the normally the best option. (3) I think that it would also be desirable to add a remark to the explanation of the data argument, something like, “Although the argument is optional, it's generally preferable to specify it explicitly.” And similarly on the help page for glm(). My two (or three) cents. John ------------------------------------------------- John Fox, Professor Emeritus McMaster University Hamilton, Ontario, Canada Web: http::/socserv.mcmaster.ca/jfoxOn Dec 17, 2018, at 3:05 AM, Martin Maechler <maech...@stat.math.ethz.ch> wrote:David Hugh-Jones on Sat, 15 Dec 2018 08:47:28 +0100 writes:I would argue examples should encourage good practice. Beginners ought to learn to keep data in data frames and not to overuse attach().Note there's no attach() there in any of these examples!otherwise at their own risk, but they have less need of explicit examples.The glm examples are nice in sofar they show both uses. I agree the lm() example(s) are "didactically misleading" by not using data frames at all. I disagree that only data frame examples should be shown. If lm() is one of the first R functions a beginneR must use -- because they are in a basic stats class, say -- it may be *better* didactically to focus on lm() in the very first example, and use data frames in a next one ... .... and instead of next one, we have the pretty clear comment ### less simple examples in "See Also" above I'm not convinced (but you can try more) we should change those examples or add more there. MartinOn Fri, 14 Dec 2018 at 14:51, S Ellison <s.elli...@lgcgroup.com> wrote:FWIW, before all the examples are changed to data frame variants, I think there's fairly good reason to have at least _one_ example that does _not_ place variables in a data frame. The data argument in lm() is optional. And there is more than one way to manage data in a project. I personally don't much like lots of stray variables lurking about, but if those are the only variables out there and we can be sure they aren't affected by other code, it's hardly essential to create a data frame to hold something you already have. Also, attach() is still part of R, for those folk who have a data frame but want to reference the contents across a wider range of functions without using with() a lot. lm() can reasonably omit the data argument there, too. So while there are good reasons to use data frames, there are also good reasons to provide examples that don't. Steve Ellison-----Original Message----- > From: R-devel[mailto:r-devel-boun...@r-project.org] On Behalf Of Ben > Bolker > Sent: 13 December 2018 20:36 > To: r-devel@r-project.org > Subject: Re: [Rd] Documentation examples for lm and glmAgree. Or just create the data frame with thosevariables in it > directly ...On 2018-12-13 3:26 p.m., Thomas Yee wrote: > > Hello,something that has been on my mind for a decade ortwo has > > been the examples for lm() and glm(). They encourage poor style > > because of mismanagement of data frames. Also, having the > > variables in a data frame means that predict() > > is more likely to work properly.For lm(), the variables should be put into a dataframe. > > As 2 vectors are assigned first in the general workspace they > > should be deleted afterwards.For the glm(), the data frame d.AD is constructed butnot used. Also, > > its 3 components were assigned first in the general workspace, so they > > float around dangerously afterwards like in the lm() example.Rather than attached improved .Rd files here, theyare put at > > www.stat.auckland.ac.nz/~yee/Rdfiles > > You are welcome to use them!Best, Thomas
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