.. efun:: string * explode(string str, string del)

  Return an array of strings, created when the string str is split into substrings as divided by del.

  .. note:: ``implode(explode(str, del), del) == str`` is always true.

  .. usage::

    ::

      function                    returns
      -------------------------------------------------------------------
      explode(" ab cd ef ", " ")  ({ "", "ab", "cd", "ef", "" })
      explode("abc", "abc")       ({ "", "" })
      explode("", "")             ({ "" })
      explode("", <whatever>)     ({ "" })
      explode("abc", "xyz")       ({ "abc" })
      explode("abc", "")          ({ "a", "b", "c" })

    .. todo:: not sure what to do with formats like this; retain as table?

  :history unknown changed: ``explode(" ab cd ef ", " ")`` formerly returned ``({ "ab", "cd", "ef" })`` instead of ``({ "", "ab", "cd", "ef", "" })``, i. e. the empty strings were ignored. The new behaviour is more consistent, because now ``implode(explode(str, del), del) == str`` is always true.
  :history 3.5.0 changed: explode("","") returns ({""}), so it is guaranteed to return a non-empty array.

  .. seealso:: :efun:`sscanf`, :efun:`implode`, :efun:`regexplode`