如何在python regex中获取可能从字符串中相同位置开始的所有重叠匹配项? [英] How to get all overlapping matches in python regex that may start at the same location in a string?

问题描述

如何在具有多个起点和终点的 Python 字符串中获取所有可能的重叠匹配项.

How do I get all possible overlapping matches in a string in Python with multiple starting and ending points.

我尝试使用正则表达式模块，而不是默认的 re 模块来引入重叠 = True 参数，但仍然缺少一些匹配项.

I've tried using regex module, instead of default re module to introduce overlapped = True argument, but still it is missing some matches.

尝试通过更简单的说明来描述我的问题:

Trying to describe my problem via a simpler illustration:

在以 a 开头并以 b

尝试了以下代码:

import regex

print(regex.findall(r'a\w+b','axaybzb', overlapped=False))

['axaybzb']

print(regex.findall(r'a\w+?b','axaybzb', overlapped=False))

['axayb']

print(regex.findall(r'a\w+b','axaybzb', overlapped=True))

['axaybzb', 'aybzb']

print(regex.findall(r'a\w+?b','axaybzb', overlapped=True))

['axayb', 'ayb']

预期输出为

['axayb', 'axaybzb', 'ayb', 'aybzb']

推荐答案

Regex 在这里不是合适的工具，我建议:

Regex are not the proper tool here, I would recommend:

• 识别输入字符串中第一个字母的所有索引
• 识别输入字符串中第二个字母的所有索引
• 根据这些索引构建所有子字符串

代码:

def find(str, ch):
    for i, ltr in enumerate(str):
        if ltr == ch:
            yield i

s = "axaybzb"
startChar = 'a'
endChar = 'b'

startCharList = list(find(s,startChar))
endCharList = list(find(s,endChar))

output = []
for u in startCharList:
    for v in endCharList:
           if u <= v:
               output.append(s[u:v+1])
print(output)

输出:

$ python substring.py 
['axayb', 'axaybzb', 'ayb', 'aybzb']

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