python regex find values with newline character also

Question

I am working on this regex problem I'm unable to solve. The regex I've made

import re
message = """[key    X] value
[key    X]  value value
[key    X]  value
value
value
value
[key     ] value
[key     ] ?
[key     ] ?"""

messageRegex = re.compile(r"\[(.*?)][\s](.*)")

for value in messageRegex.findall(message):
    print(value)

The output to this is, as given below and not everything is getting captured.

('key    X', 'value') ('key\tX', 'value value') ('key\tX', 'value')
('key\t ', 'value') ('key\t ', '?') ('key\t ', '?')

I would expect the output to look like

('key    X', 'value') ('key\tX', 'value value') ('key\tX', 'value \nvalue \nvalue \nvalue')
('key\t ', 'value') ('key\t ', '?') ('key\t ', '?')

Answer 1

You may use

(?m)^\[([^][]*)]\s+(.*(?:\n(?!\[[^][]*]).*)*)

See the regex demo

Details

• ^ - start of a line
• \[ - [
• ([^][]*) - Group 1: any 0+ chars other than [ and ]
• ] - a ] char
• \s+ - 1+ whitespaces
• (.*(?:\n(?!\[[^][]*]).*)*) - Group 2:
  • .* - the rest of the line
  • (?:\n(?!\[[^][]*]).*)* - zero or more repetitions of:
    • \n(?!\[[^][]*]) - a newline not followed with a [...] substring
    • .* - the rest of the line

Python demo:

import re
message = """[key    X] value
[key    X]  value value
[key    X]  value
value
value
value
[key     ] value
[key     ] ?
[key     ] ?"""

messageRegex = re.compile(r"^\[([^][]*)]\s+(.*(?:\n(?!\[[^][]*]).*)*)", re.M)

for value in messageRegex.findall(message):
    print(value)

Output:

('key    X', 'value')
('key    X', 'value value')
('key    X', 'value\nvalue\nvalue\nvalue')
('key     ', 'value')
('key     ', '?')
('key     ', '?')