Hi Esmail, Try this:
vars=c('X.1', 'X.2', 'X.3', 'X.4', 'X.5') bits=c(1, 0, 1, 1, 0) paste(vars[which(bits==1)],collapse="+") HTH, Jorge On Tue, May 6, 2008 at 3:06 PM, Esmail Bonakdarian <[EMAIL PROTECTED]> wrote: > Hello, > > Still a newbie with R, though I have learned a lot from reading > this list. I'm hoping someone can help with this question: > > I have two vectors, one for variables, and one for bits. > > I want to build a string (really a formula) based on the values in my > vector of 1s and 0s in bits. If I have a one, I want to include the > corresponding entry in the vars vector, otherwise ignore it. Of course > the "bits" vector will not stay the same. > > So for example: > > vars=c('X.1', 'X.2', 'X.3', 'X.4', 'X.5') > > bits=c(1, 0, 1, 1, 0) > ones=which(bits==1) > > should yield: > > "X.1 + X.3 + X.4" > > where as > > bits=c(1, 1, 0, 0, 0) > > would yield > > "X.1 + X.2" > > the "which" operator gives me the index values, is there an easy and > *efficient* way to build this string so that I can pass it on to glm? > I can probably hack some ugly code together to do this, but it won't > be efficient, and it won't be elegant :-) > > Can anyone help? > > Thanks! > > ______________________________________________ > 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. [[alternative HTML version deleted]] ______________________________________________ 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.