正则表达式匹配前面没有字符串的字符 [英] Regex match characters when not preceded by a string

问题描述

我试图在标点符号之后匹配空格，以便我可以拆分大量文本，但我看到一些常见的边缘情况，包括地点、标题和常见缩写:

I am trying to match spaces just after punctuation marks so that I can split up a large corpus of text, but I am seeing some common edge cases with places, titles and common abbreviations:

I am from New York, N.Y. and I would like to say hello! How are you today? I am well. I owe you $6. 00 because you bought me a No. 3 burger. -Sgt. Smith

我将它与 Python 3 中的 re.split 函数一起使用，我想得到这个:

I am using this with the re.split function in Python 3 I want to get this:

["I am from New York, N.Y. and I would like to say hello!",
"How are you today?",
"I am well.",
"I owe you $6. 00 because you bought me a No. 3 burger."
"-Sgt. Smith"]

这是目前我的正则表达式:

This is currently my regex:

(?<=[\.\?\!])(?<=[^A-Z].)(?<=[^0-9].)(?<=[^N]..)(?<=[^o].)

我决定首先尝试修复No.，最后两个条件.但它依赖于独立匹配 N 和 o ，我认为这会在其他地方出现误报.我不知道如何让它在句点后面只生成字符串 No .然后，我将对 Sgt. 和我遇到的任何其他问题"字符串使用类似的方法.

I decided to try to fix the No. first, with the last two conditions. But it relies on matching the N and the o independently which I think is going to case false positives elsewhere. I cannot figure out how to get it to make just the string No behind the period. I will then use a similar approach for Sgt. and any other "problem" strings I come across.

我正在尝试使用类似的东西:

I am trying to use something like:

<代码>(?<=[\.\?\!])(?<=[^AZ].)(?<=[^0-9].)^(?<=^No$)

但在那之后它没有捕获任何东西.我怎样才能让它排除某些我希望在其中包含句点的字符串，而不是捕获它们?

But it doesn't capture anything after that. How can I get it to exclude certain strings which I expect to have a period in it, and not capture them?

这是我的情况的正则表达式:https://regexr.com/4sgcb

Here is a regexr of my situation: https://regexr.com/4sgcb

推荐答案

只使用一个正则表达式会很棘手 - 正如评论中所述，有很多边缘情况.

Doing it with only one regex will be tricky - as stated in comments, there are lots of edge cases.

我自己会分三步完成:

1. 用一些特殊字符替换应该保留的空格 (re.sub)
2. 拆分文本(re.split)
3. 用空格替换特殊字符

例如:

import re

zero_width_space = '\u200B'

s = 'I am from New York, N.Y. and I would like to say hello! How are you today? I am well. I owe you $6. 00 because you bought me a No. 3 burger. -Sgt. Smith'

s = re.sub(r'(?<=\.)\s+(?=[\da-z])|(?<=,)\s+|(?<=Sgt\.)\s+', zero_width_space, s)
s = re.split(r'(?<=[.?!])\s+', s)

from pprint import pprint
pprint([line.replace(zero_width_space, ' ') for line in s])

打印:

['I am from New York, N.Y. and I would like to say hello!',
 'How are you today?',
 'I am well.',
 'I owe you $6. 00 because you bought me a No. 3 burger.',
 '-Sgt. Smith']

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