Tobin, Jared wrote: > Hello r-help, > > I have a lengthy vector of data (with values anywhere from 1-200), and > another index vector of 'groups' representing values 0-2, 3-5, 6-8, ... > of length 67. The index vector has the structure (1, 4, 7, ... , 196, > 199), where each value is the midpoint of each respective group. > > I'm trying to convert the data vector such that values falling into each > group are changed to the 'number' of that group. That is, the position > of the midpoint of that group in the index vector. For example, 4 or 5 > would become a 2; 6 would become 3; 9 or 10 would become 4, and so on. > > Haven't had any success thus far -- does anyone know of a simple method > offhand? > > I've started by converting the data vector to a vector of the midpoints > of each group, via > >> round(data.vector/3)*3 + 1 >> > > But haven't been able to accomplish much past that. I'm guessing it can > be accomplished via a simple loop or otherwise. > > You could convert midpoints to breakpoints and use cut(). Do you know that each group contains 3 consecutive values? Otherwise it gets a bit sticky. If it does, use
as.integer(cut(data.vector, breaks=seq(-.5,200.5,3))) (which also works for other sets of breakpoints) or just use integer division data.vector %/% 3 + 1 > Thanks, > > -- > > jared tobin, student research assistant > fisheries and oceans canada > [EMAIL PROTECTED] > > ______________________________________________ > 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. > -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ 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.
