All - I have a large data frame that looks like
ID p1 p2 p3...p20 Lat1 Lat2 Lat3...Lat20 Long1 Long2 Long3...Long20 1 0 0 1 0 NA NA 29.xx NA NA NA -89.xx NA 2 1 0 0 1 27.xx NA NA 29.00 -88.00 NA NA -89.xx 3 0 0 0 0 NA NA NA NA NA NA NA NA ... [truncated] where length(ID) = 1300 and the zeroes and ones in the p1-p20 column correspond to values in the Lat1-Lat20 and Long1-Long20 columns; a 0 indicates no corresponding value and 1 indicates there is a corresponding value. I'd like to create a dataframe that is ID p Lat Long 1 3 29.xx -89.xx 2 1 27.xx -88.xx 2 20 29.xx -89.xx ... and so on, such that for every ID I have, there is a corresponding row with each Latn and Longn that may exist. My problem is that I don't know how to do that in R. I can set up simple "for" loops, but I don't know how to set up something that has a "for" and an "if/else" statement. And frankly, with the number of pX, LatX, and LongX, I think that my if/else statement would be huge and unwieldly. Could anyone offer any assistance? Thanks for your help - SR Steven H. Ranney ______________________________________________ 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.
