I dont really understand you what you want now. What is exactly you are traing to achive?
Would you like from string "Hello World", change it to "H e l l o W o r l d"?
And what concerns your 1st question in your 1st post, YES, you are allowed to split nothing. If you have in mind example "thisIsTestString" - here is no white spaces, so code wont split - but there will still be NO error. There will be 1 array (same as 1 string), in a word - wortheless to have an array, but as said, no error - so you are allowed to split.