Split a String at every 3rd comma in Java

Question

I have a string that looks like this:

0,0,1,2,4,5,3,4,6

What I want returned is a String[]

Answer 1

Nice one for the coding dojo! Here's my good old-fashioned C-style answer:

If we call the bits between commas 'parts', and the results that get split off 'substrings' then:

n is the amount of parts found so far, i is the start of the next part, startIndex the start of the current substring

Iterate over the parts, every third part: chop off a substring.

Add the leftover part at the end to the result when you run out of commas.

List result = new ArrayList();
int startIndex = 0;
int n = 0;
for (int i = x.indexOf(',') + 1; i > 0; i = x.indexOf(',', i) + 1, n++) {
    if (n % 3 == 2) {
        result.add(x.substring(startIndex, i - 1));
        startIndex = i;
    }
}
result.add(x.substring(startIndex));