Split string based on regex but keep delimiters

Question

I\'m trying to split a string using a variety of characters as delimiters and also keep those delimiters in their own array index. For example say I want to split the string:

Answer 1

To answer your question, "Why?", it's because your entire expression is a lookahead assertion. As long as that assertion is true at each character (or maybe I should say "between"), it is able to split.

Also, you cannot group within character classes, e.g. (<=) is not doing what you think it is doing.