Split string by delimiter only if not wrapped in certain pattern
python, regex
Solution
Update: Since you mentioned that the brackets may be nested, I regret to inform you that a regex solution is not possible in Python. The following can work only if the angle brackets are always balanced and never nested nor escaped:
>>> import re
>>> s = "first token, <second token part 1, second token part 2>, third token"
>>> regex = re.compile(",(?![^<>]*>)")
>>> regex.split(s)
['first token', ' <second token part 1, second token part 2>', ' third token']
>>> [item.strip(" <>") for item in _]
['first token', 'second token part 1, second token part 2', 'third token']
The regex `,(?![^<>]*>)` splits on commas only if the next angle bracket that follows isn't a closing angle bracket.
Nested brackets preclude this or any other regex solution from working in Python. You either need a language that supports recursive regexes (like Perl or .NET languages), or use a parser.
Problem
I am trying to split a string into a list by a delimiter (let's say `,`) but the delimiter character should be considered the delimiter only if it is not wrapped in a certain pattern, in my particular case `<>`. IOW, when a comma is nested in `<>`, it is ignored as a delimiter and becomes just a regular character not to be delimited by. So if I have the following string: ``` "first token, <second token part 1, second token part 2>, third token" ``` it should split into ``` list[0] = "first token" list[1] = "second token part 1, second token part 2" list[2] = "third token" ``` Needless to say, I cannot just do a simple split by `,` because that will split the second token into two tokens, `second token part 1` and `second token part 2`, as they have a comma in between them. How should I define the pattern to do it using `Python RegEx`?