Hi
r-help-boun...@r-project.org napsal dne 10.02.2009 12:02:53: > Hello, > > suppose I have a data frame: > > > mat > id age > 1 NA NA > 2 NA NA > 3 NA NA > 4 NA NA > 5 NA NA > > Then I attach the data frame: > > > attach(mat) Look into docs what attach does. If you do not understand environments use attach with great care The database is not actually attached. Rather, a new environment is created on the search path and the elements of a list (including columns of a data frame) or objects in a save file or an environment are copied into the new environment. If you use <<- or assign to assign to an attached database, you only alter the attached copy, not the original object. (Normal assignment will place a modified version in the user's workspace: see the examples.) For this reason attach can lead to confusion. > > I assign some new values... > > > id <<- sample(100,5) > > age <<- rnorm(5,mean=30) > > Then I want to create a new data frame from the variables id and age which > still are attached to position 2 of the R environment... > > > new_mat <- data.frame(ls(pos=2)) # I want to rescue ALL variables that were > created by attach(mat) > > > new_mat > ls.pos...2. > 1 age > 2 id > > But this leads to a bogus object... how can I rescue the updated id and age > values into new_mat? What about not using attach and transform mat directly > mat$age <- rnorm(5,mean=30) > mat$id <- sample(100,5) > mat id age 1 24 29.17842 2 88 31.22606 3 32 30.81540 4 5 29.31528 5 11 29.32775 Regards Petr > > > Regards, > > David > > -- > Jetzt 1 Monat kostenlos! GMX FreeDSL - Telefonanschluss + DSL > für nur 17,95 Euro/mtl.!* http://dsl.gmx.de/?ac=OM.AD.PD003K11308T4569a > > ______________________________________________ > R-help@r-project.org mailing list > 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 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.
