On 4 Aug 2003 at 11:09, Simon Fear wrote: > Peter is right, but there is a point here: it would be nice if > attach(my.dframe) would do nothing - or at least warn - if my.dframe was > already in the search list. Like library(). Attaching twice is almost > bound > to be an error?
Not necessarily. If you changed the data --- as when debugging a data file and repeatedly sourcing it in --- you need to attach repeatedly. Of course, you should detach() first, but that is not a requirement today. Kjetil Halvorsen > Of course in many circumstances it might be better to use with() than > attach() - if you haven't come across with(), it works like attach() > with an > inbuilt detach() when the parentheses close. > > Aside 1: it would also be nice if ?attach pointed to ?with. Is this kind > of > suggestion best sent to r-help or r-devel? > > Aside 2: is with() efficient, or does it create a copy of the dataset? > > SF > > > -----Original Message----- > From: Peter Dalgaard BSA [mailto:[EMAIL PROTECTED] > Sent: 04 August 2003 00:52 > To: Andreas Eckner > Cc: [EMAIL PROTECTED] > Subject: Re: [R] Problem with data.frames > > > Security Warning: > If you are not sure an attachment is safe to open please contact > Andy on x234. There are 0 attachments with this message. > ________________________________________________________________ > > Andreas Eckner <[EMAIL PROTECTED]> writes: > > > Hi, > > > > I just encountered a problem in R that may easily be fixed: If one > uses > > attach for a data.frame e.g. 10000 times and forgets detach, then R > gets > > incredibly slow (less then 10% of the original speed). > > R also gets incredibly slow if you create 10000 copies of your data > set, which is effectively the same thing! The fix is: Don't do that... > > -- > O__ ---- Peter Dalgaard Blegdamsvej 3 > c/ /'_ --- Dept. of Biostatistics 2200 Cph. N > (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 > ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > > > Simon Fear > Senior Statistician > Syne qua non Ltd > Tel: +44 (0) 1379 644449 > Fax: +44 (0) 1379 644445 > email: [EMAIL PROTECTED] > web: http://www.synequanon.com > > Number of attachments included with this message: 0 > > This message (and any associated files) is confidential and\...{{dropped}} > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
