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

Well, you can use lookaround to split at points between characters without consuming the delimiters:

(?<=[()>*-;\s])|(?=[()>*-;\s])

This will create a split point before and after each delimiter character. You might need to remove superfluous whitespace elements from the resulting array, though.

Quick PowerShell test (| marks the split points):

PS Home:\> 'if (x>1) return x * fact(x-1);' -split '(?<=[()>*-;\s])|(?=[()>*-;\s])' -join '|'
if| |(|x|>|1|)| |return| |x| |*| |fact|(|x|-|1|)|;|

Answer 2

How about this pattern?

(\w+)|([\p{P}\p{S}])

Answer 3

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.