Question

I’m trying to extract “entries” from a text file using a regular expression. Each line of the file is a separate entry unless the line begins with whitespace, in which case that line is a continuation of the previous line.

Example:

import re

INPUT = """\
This is entry 1.
This
 is
  entry 2.
And this is entry 3.
This
 is
 entry
 4."""

OUTPUT = ["This is entry 1.",
          "This\n is\n  entry 2.",
          "And this is entry 3.",
          "This\n is\n entry\n 4."]

# What should the pattern be?
PATTERN = re.compile("(.+)(?=\n|$)")

assert PATTERN.findall(INPUT) == OUTPUT

What should PATTERN be to match all the entries?

Answer 1

I think figured it out.

The trick is “. (which doesn’t match newlines) or a newline followed by whitespace”.

PATTERN = re.compile(r"(?:.|\n\s)+")