Two questions about matrix indexing: Is is correct that V <- V[lower.tri(V, diag=TRUE)] returns the lower triangular of matrix V, that is: all elements above diagonal are set to zero? I understand that the triangle of matrix elements of V for which lower.tri is TRUE are returned while the others (above diagonal) are set to zero (or NA ???).
If D and B are vectors of logicals, what does V contain after V <- v[D, B, drop=FALSE] ? I guess that elements are returned if both indexes D and B are TRUE, but I'm not really convinced... (And again, what about the other elements?) These are probably tutorial questions, but I'm still not sure after reading "R Language Definition (draft): Evaluation of expressions" and applicable sections of "The R Reference Manual". Thanx! W. Beldman ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
