Interesting thread, but perhaps better moved elsewhere at some point? The nb class is really only a list representing a by-row sparse matrix, one row per list component, with attributes and corner-case code to mark geometries with no neighbours for a given definition of neighbour. The set operations were contributed by Nicholas Lewin-Koh possibly in 2001, possibly before, but IIRC the question of generics was considered, but we didn't add standard generics ([, c, etc.). So although the underlying list class could be made a character vector, I think getting a valid nb object back out was the blocking point. It is worth raising as an issue in the spdep repo!
Roger -- Roger Bivand Emeritus Professor Norwegian School of Economics Postboks 3490 Ytre Sandviken, 5045 Bergen, Norway [email protected] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
