Is there a regex that would work with String.split() to break a String into contiguous characters - ie split where the next character is different to the previous character?
Here's the test case:
String regex = "your answer here";
String[] parts = "aaabbcddeee".split(regex);
System.out.println(Arrays.toString(parts));
Expected output:
[aaa, bb, c, dd, eee]
Although the test case has letters only as input, this is for clarity only; input characters may be any character.
Please do not provide "work-arounds" involving loops or other techniques.
The question is to find the right regex for the code as shown above - ie only using split() and no other methods calls. It is not a question about finding code that will "do the job".
It is totally possible to write the regex for splitting in one step:
"(?<=(.))(?!\\1)"
Since you want to split between every group of same characters, we just need to look for the boundary between 2 groups. I achieve this by using a positive look-behind just to grab the previous character, and use a negative look-ahead and back-reference to check that the next character is not the same character.
As you can see, the regex is zero-width (only 2 look around assertions). No character is consumed by the regex.