> On 23 May 2016, at 13:43 , Ivan Calandra <ivan.calan...@univ-reims.fr> wrote: > > Hi John, > > This is indeed documented, but you'll have to look at the function formula(): > ?formula > > Regarding the dot (.), here is the explanation from the help of formula(): > "There are two special interpretations of . in a formula. The usual one is in > the context of a data argument of model fitting functions and means ‘all > columns not otherwise in the formula’: see terms.formula. In the context of > update.formula, only, it means ‘what was previously in this part of the > formula’."
Actually, it is debatable which one of those deserve to be called "usual". Once upon a time, in the heyday of John Tukey, it might have been usual to have data set of a few hundred rows and, like, a dozen columns, exactly one of which being the response. Not so much these days, I'd say. -pd > > HTH, > Ivan > > -- > Ivan Calandra, PhD > Scientific Mediator > University of Reims Champagne-Ardenne > GEGENAA - EA 3795 > CREA - 2 esplanade Roland Garros > 51100 Reims, France > +33(0)3 26 77 36 89 > ivan.calan...@univ-reims.fr > -- > https://www.researchgate.net/profile/Ivan_Calandra > https://publons.com/author/705639/ > > Le 23/05/2016 à 13:26, John Sorkin a écrit : >> The syntax >> mydat <- data.frame( y,x ) >> fit1 <- lm( y~., data=mydat ) >> appears to perform a multivariable regression of y on every non-y variable >> in the data frame mydat. I can not find this syntax (y~.) in R >> documentation. Is y~. a supported feature of the R language? Where can I >> find it documented? I would hate to write code that is dependent on a >> non-supported, non-documented language feature. >> Thank you, >> John >> John David Sorkin M.D., Ph.D. >> Professor of Medicine >> Chief, Biostatistics and Informatics >> University of Maryland School of Medicine Division of Gerontology and >> Geriatric Medicine >> Baltimore VA Medical Center >> 10 North Greene Street >> GRECC (BT/18/GR) >> Baltimore, MD 21201-1524 >> (Phone) 410-605-7119 >> (Fax) 410-605-7913 (Please call phone number above prior to faxing) >> >> Confidentiality Statement: >> This email message, including any attachments, is for ...{{dropped:8}} > > ______________________________________________ > 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. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ 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.
