Hi I have say a large vector of 3500 digits. Initially the digits are 0s and 1s. I need to check for a rule to change some of the 0s to -1s in this vector. But once I change a 0 to -1 then I need to start applying the rule to change the next 0 only after I see the next 1 in the vector.
Say for example x = (0,0,0,0,0,0,0,1,0,0,1,1,0,0,1,0,0,0,1) I need to traverse from the 9th element to the last ( because the first occurrence of 1 is at 8) . Let us assume that according to our rule we change the 13th element (only 0s can be changed) to -1. Now we need to go to the next occurrence of 1 (which is 15) and begin the rule application from the 16th till the end of the vector and once replaced a 0 to a -1 then start again from the next 1. How do we code this? I 'feel' recursion is the best possible solution but I am not a programmer and will await experts' views. If this is not a typical R-forum question then my advance apologies. Many thx -- 'Raghu' [[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.