Python “split” on empty new line

Question

Trying to use a python split on a \"empty\" newline but not any other new lines. I tried a few other example I found but none of them seem to work.

Data example:

Answer 1

This works in the case where multiple blank lines should be treated as one.

import re

def split_on_empty_lines(s):

    # greedily match 2 or more new-lines
    blank_line_regex = r"(?:\r?\n){2,}"

    return re.split(blank_line_regex, s.strip())

The regex is a bit odd.

1. Firstly, the greedy matching means that many blank lines count as a single match, i.e. 6 blank lines makes one split, not three splits.
2. Secondly, the pattern doesn't just match \n but either \r\n (for Windows) or \n (for Linux/Mac).
3. Thirdly, the group (denoted by parentheses) needs to have ?: inside the
   opening parenthesis to make it a "non-capturing" group, which changes the behaviour of re.split.

For example:

s = """

hello
world

this is







a test

"""

split_on_empty_lines(s)

returns

['hello\nworld', 'this is', 'a test']