tweak to r63950

git-svn-id: https://svn.r-project.org/R/trunk@63952 00db46b3-68df-0310-9c12-caf00c1e9a41
vapply(.) instead of for(.) loop [good part of r63942]

git-svn-id: https://svn.r-project.org/R/trunk@63953 00db46b3-68df-0310-9c12-caf00c1e9a41
"last" tweak


git-svn-id: https://svn.r-project.org/R/trunk@63954 00db46b3-68df-0310-9c12-caf00c1e9a41