On Sat, Apr 29, 2017 at 10:40 AM, Bert Gunter <bgunter.4...@gmail.com> wrote:
> Also: > > "I was just a bit frustrated that R wouldn't generate dummy variable > names on the fly." > > That is false. See ?lm and ?model.matrix > I am not sure what you mean. I thought if there is a three level dummy variable, then it would generate a dummy.1, dummy.2 in lm() > > -- Bert > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Sat, Apr 29, 2017 at 1:06 AM, Göran Broström <goran.brost...@umu.se> > wrote: > > > > > > On 2017-04-29 06:45, Mike C wrote: > >> > >> Thanks Rolf. I was just a bit frustrated that R wouldn't generate > >> dummy variable names on the fly. > >> > >> Also, another question, if I want to put column 5 at column 3, > >> > >> dat[, 3:5] <- dat[, c(5,3,4)] > >> > >> It does not work, why? > > > > > > It "works", but you need to shuffle the names in the same way: > > > > names(dat)[3:5] <- names(dat)[c(5,3,4)] > > > > Better(?): > > > > perm <- c(1,2,5,3,4) > > dat <- dat[perm] > > > > dat is a list. > > > > Göran > > > > > >> > >> ________________________________ From: Rolf Turner > >> <r.tur...@auckland.ac.nz> Sent: Friday, April 28, 2017 10:48:42 PM > >> To: C W Cc: r-help Subject: Re: [FORGED] Re: [R] How create columns > >> for squared values from previous columns? > >> > >> On 29/04/17 13:21, C W wrote: > >>> > >>> I came up with this solution, > >>> > >>>> cbind(dat, dat[, 1:3]^2) > >>> > >>> X1 X2 X3 X4 X5 X1 X2 > >>> X3 1 0.72776481 -1.1332612 -1.9857503 0.46189400 -0.09016379 > >>> 0.529641625 1.28428102 3.9432044 2 0.05126592 0.2858707 > >>> 0.9075806 1.27582713 -0.49438507 0.002628194 0.08172203 0.8237026 3 > >>> -0.40430146 0.5457195 -1.1924042 0.15025594 1.99710475 > >>> 0.163459669 0.29780978 1.4218277 4 1.40746971 -1.2279416 > >>> 0.3296075 0.84411774 -0.52371619 1.980970990 1.50784058 0.1086411 5 > >>> -0.53841150 0.4750082 -0.4705148 0.05591914 -0.31503500 > >>> 0.289886944 0.22563275 0.2213842 6 0.90691210 0.7247171 > >>> 0.8244184 0.73328097 -1.05284737 0.822489552 0.52521494 0.6796657 > >>> > >>> But, you would NOT ONLY get undesired variable names, BUT ALSO > >>> duplicated names. I suppose I can use paste() to solve that? > >>> > >>> Any better ideas? > >> > >> > >> Well, if the names bizzo is your only worry, you could hit the > >> result with data.frame() *after* cbinding on the squared terms: > >> > >> dat <- matrix(rnorm(30),ncol=5) dat <- cbind(dat,dat[,1:3]^2) dat <- > >> data.frame(dat) names(dat) > >> > >> And as you indicate, the names of a data frame are easily adjusted. > >> > >> I wouldn't lose sleep over it. > >> > >> cheers, > >> > >> Rolf Turner > >> > >> P.S. You could also do > >> > >> names(dat) <- make.unique(names(dat)) > >> > >> to your original idea, to get rid of the lack of uniqueness. The > >> result is probably "undesirable" but. > >> > >> R. T. > >> > >> -- Technical Editor ANZJS Department of Statistics University of > >> Auckland Phone: +64-9-373-7599 ext. 88276 > >> > >> [[alternative HTML version deleted]] > >> > >> ______________________________________________ R-help@r-project.org > >> mailing list -- To UNSUBSCRIBE and more, see > >> https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the > >> posting guide http://www.R-project.org/posting-guide.html and provide > >> commented, minimal, self-contained, reproducible code. > >> > > > > ______________________________________________ > > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide http://www.R-project.org/ > posting-guide.html > > and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/ > posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
