Please repost your question in plain text rather than HTML - you can see below that your code got rather mangled. Please also include some sample data using dput() - made-up data of similar form is fine, but it's very hard to answer a question based on guessing what the data look like.
Sarah On Wed, Jun 24, 2015 at 2:26 PM, giacomo begnis <gmbeg...@yahoo.it> wrote: > Hi, I have a dataset (728 obs) containing three variables code of a company, > year and revenue. Some companies have a complete history of 5 years, others > have not a complete history (for instance observations for three or four > years).I would like to determine the companies with a complete history using > a dummy variables.I have written the following program but there is somehting > wrong because the dummy variable that I have create is always equal to > zero.Can somebody help me?Thanks, gm > > z<-read.table(file="c:/Rp/cddat.txt", sep="", header=T) > attach(z) > n<-length(z$cod) // number of obs dataset > > d1<-numeric(n) // dummy variable > > for (i in 5:n) { > if (z$cod[i]==z$cod[i-4]) // cod is the code of a company > { d1[i]<=1} else { d1[i]<=0} // d1=1 for a company with > complete history, d1=0 if the history is not complete }d1 > When I run the program d1 is always equal to zero. Why? > Once I have create the dummy variable with subset I obtains the code of the > companies with a complete history and finally with a merge I determine a > panel of companies with a complete history.But how to determine correctly > d1?My best regards, gm > > > > [[alternative HTML version deleted]] > -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.