For my personal programming, I find using with( ) is safer then attach( ) and quicker then $. For my teaching, I usually try my students to be capable of doing things "the hard way" so they understand what's under the hood, and only then introduce then to the shortcuts. Thus, I recommend introducing with( ) after they are familiar with $ or [[ ]], but avoid attach( ).
Jonathan -- Jonathan Rosenblatt www.john-ros.com On Wed, Sep 22, 2010 at 10:36 AM, Gavin Simpson <[email protected]>wrote: > On Tue, 2010-09-21 at 21:34 -0700, Joshua Wiley wrote: > > Hi all, > > > > I am wondering if anyone teaches the attach function to new students > > and if so, why? > > I don't use attach() at all; too easy to make mistakes that are > difficult to track down. I tend not to use $ either as that encourages > people to use it to go fiddling in the bowels of other lists (objects); > model$residuals might be OK for lm() models (though not if you've used > na.exclude for example) but students might be surprised with what they > get with more complex modelling functions with different residuals. > > If I was really teaching R, I would mention attach() and then show why > it is bad so I've dealt with the issue on my terms. > > G > > > I have never taught a class using R, but in small tutorials and > > providing direct help, I have run across this issue several times. I > > have always avoided it, but a couple of times, students had learned to > > use it in a class (though without much detail) and were rather grumpy > > with me for using full variable names or with(). New converts, > > particularly from GUIs like SPSS, already tend to be leery of R, and I > > hate to make working at the command line more onerous since any typing > > is more than they are used to, but at the same time a discussion of > > environments, which I think is necessary to avoid trouble with attach, > > does not seem like beginner material either. > > > > I have wondered about this many times, but was just reminded again by > > an R-help post. > > > > Thanks, > > > > Josh > > > > -- > %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% > Dr. Gavin Simpson [t] +44 (0)20 7679 0522 > ECRC, UCL Geography, [f] +44 (0)20 7679 0565 > Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk > Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ > UK. WC1E 6BT. [w] http://www.freshwaters.org.uk > %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% > > _______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-sig-teaching > [[alternative HTML version deleted]] _______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-sig-teaching
