When I iterated over the string 1000x the time to execute was almost the exact same.
I even tested two different regular expressions to make sure I wasn’t being to liberal with my pattern. The difference was negligible.
Test String: "hEll0 WoRLD please hElP me"
Standard Regular Expression: "(\\w)+\\s?"
Boundary Regular Expression: "(\\b\\w)"
Single (regular regex)
Time to parse using regex: 0.003947
Time to parse using componentsSeparatedByString: 0.001246
Single (boundary regex)
Time to parse using regex: 0.003747
Time to parse using componentsSeparatedByString: 0.000668
Time to parse using regex: 0.511170
Time to parse using componentsSeparatedByString: 0.538784
Time to parse using regex: 0.555807
Time to parse using componentsSeparatedByString: 0.485708
Here is the test project