rm.prefix() and rm.suffix() to remove a
given prefix or suffix from character vector elements.whichRepeated(), whichNA(),
whichMin()/whichMax() when
loc = "all" and repeats() now don’t attempt to
preserve names when no indices or duplicates are found,
respectively.
The C code for whichRepeated() now avoids passing an
invalid data pointer from a 0-length vector to memcpy(),
which previously caused undefined behaviour. Thanks to Prof. Brian D.
Ripley for reporting.