匹配最小可能的句子

Question

Text:

One sentence here, much wow. Another one here. This is O.N.E. example n. 1, a nice one to understand. Hope it's clear now!

Regex: (?<=\.\s)[AZ].+?nice one.+?\.(?=\s[AZ])

Result: Another one here. This is ONE example n. 1, a nice one to understand. Another one here. This is ONE example n. 1, a nice one to understand.

How can I do to obtain This is ONE example among n. 1, a nice one to understand. This is ONE example among n. 1, a nice one to understand. ? (ie the smallest possible sentence that matches the regex)

Answer 1

Just insert a greedy .* in front of the expression

.*\.\s([A-Z].+?nice one.+?\.(?=\s[A-Z]))

Answer 2

Here is a little bit of a different approach just splitting the entire text and then filtering out what you are after:

import re
s = "One sentence here, much wow. Another one here. This is O.N.E. example n. 1, a nice one to understand. Hope it's clear now!"
result = [x for x in re.split(r'(?<=\B.\.)\s*',s) if 'nice one' in x][0]
print(result) # This is O.N.E. example n. 1, a nice one to understand.

Not sure how many edge-cases you have got but here I used re.split() with the following pattern: (?<=\B.\.)\s* . This would mean:

• (?<=\B.\.) - A positive lookbehind to assert position is after a position where \b (a word-boundary) does not apply, followed by a literal dot.
• \s* - 0+ Whitespace characters.

With the resulting array it won't be too much problem to check which element is holding your desired words "nice one".

See an online demo

Answer 3

You could exclude matching a dot, and only match the dot incase of an uppercase char followed by a dot, or a dot followed by a space and digit.

(?:(?<=\.\s)|^)[A-Z][^.A-Z]*(?:(?:[A-Z]\.|\.\s\d)[^.A-Z]*)*\bnice one\b.+?(?=\s[A-Z])

• (?:(?<=\.\s)|^) Assert a . and whitespace char to the left or the start of the string
• [AZ][^.AZ]* Match an uppercase char AZ and 0+ times any char except a dot or uppercase char
• (?: Non capture group
  • (?:[AZ]\.|\.\s\d) Match either AZ and . or match . whitespace char and digit
  • [^.AZ]* Optionally match any char except a . or uppercase char
• )* Close group and optionally repeat
• \bnice one\b.+?(?=\s[AZ]) Match nice one and match until asserting a whitspace char and uppercase char to the right

Regex demo