I'd suggest from: Python Docs
  str.rsplit([sep[, maxsplit]])
  
  Return a list of the words in the string, using sep as the delimiter
  string. If maxsplit is given, at most maxsplit splits are done, the
  rightmost ones. If sep is not specified or None, any whitespace string
  is a separator. Except for splitting from the right, rsplit() behaves
  like split() which is described in detail below.
so to answer your question yes.
EDIT:
It depends on how you wish to index your strings too, it looks like Rstring does it from the right, so if your data is always "rightmost" you could index by 0 (or 1, not sure how python indexes), every time, rather then having to do a size check of the returned array.