Gabor came close to the situation I had yesterday that prompted me to write a local version of 'lower.tri'. It was approximately:
x[sub, sub][lower.tri(x[sub,sub])] Pat Gabor Grothendieck wrote: > On 8/6/06, Prof Brian Ripley <[EMAIL PROTECTED]> wrote: > >> Is there a case to be made for this? If so, where is it? >> >> (I don't find x[lower.tri(x)] harder to write than lower.tri(x, >> value=TRUE), and wonder why you do? > > > The reasons are > > 1. x might be the result of an expression. Without value= > one must store the result of that expression in a variable, x, first: > > x <- outer(1:6, 1:6, "+") > x[lower.tri(x)] > > but with the proposed value= argument one could just use function > composition: > > lower.tri(outer(1:6, 1:6, "+"), value = TRUE) > > 2. the whole object approach of R encourages working with the objects > themselves rather than indexes and value= is consistent with that. > > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
