如何提取两个标记之间的子字符串？

古城微笑少年丶 2022-11-25 04:14 18阅读 0赞

本文翻译自：[How to extract the substring between two markers?][How to extract the substring between two markers]

*Let's say I have a string `'gfgfdAAA1234ZZZuijjk'` and I want to extract just the `'1234'` part.* **假设我有一个字符串`'gfgfdAAA1234ZZZuijjk'`而我只想提取`'1234'`部分。**

*I only know what will be the few characters directly before `AAA` , and after `ZZZ` the part I am interested in `1234` .* **我只知道`AAA`之前和`ZZZ`之后我对`1234`感兴趣的那几个字符是什么。**

*With `sed` it is possible to do something like this with a string:* **使用`sed`可以用字符串执行以下操作：**

echo "$STRING" | sed -e "s|.*AAA$.*$ZZZ.*|\1|"

*And this will give me `1234` as a result.* **结果是我会得到`1234` 。**

*How to do the same thing in Python?* **如何在Python中做同样的事情？**

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### \#1楼 ###

参考：[https://stackoom.com/question/jA5L/如何提取两个标记之间的子字符串][https_stackoom.com_question_jA5L]

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### \#2楼 ###

*Just in case somebody will have to do the same thing that I did.* **以防万一某人必须做与我相同的事情。** *I had to extract everything inside parenthesis in a line.* **我必须在一行中提取括号内的所有内容。** *For example, if I have a line like 'US president (Barack Obama) met with ...' and I want to get only 'Barack Obama' this is solution:* **例如，如果我有一条类似“美国总统（巴拉克·奥巴马）与...会面……”这样的句子，而我只想得到“巴拉克·奥巴马”，这就是解决方案：**

regex = '.*$(.*?)$.*'
    matches = re.search(regex, line)
    line = matches.group(1) + '\n'

*Ie you need to block parenthesis with `slash \\` sign.* **也就是说，您需要使用`slash \\`符号来阻止括号。** *Though it is a problem about more regular expressions that Python.* **尽管这是关于Python的更多正则表达式的问题。**

*Also, in some cases you may see 'r' symbols before regex definition.* **另外，在某些情况下，您可能会在正则表达式定义之前看到“ r”符号。** *If there is no r prefix, you need to use escape characters like in C. [Here][] is more discussion on that.* **如果没有r前缀，则需要像C中那样使用转义字符。 [此处][Here]对此进行了更多讨论。**

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### \#3楼 ###

>>> s = '/tmp/10508.constantstring'
    >>> s.split('/tmp/')[1].split('constantstring')[0].strip('.')

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### \#4楼 ###

> *With sed it is possible to do something like this with a string:* **使用sed可以用字符串执行以下操作：**

`echo "$STRING" | sed -e "s|.*AAA\$.*\$ZZZ.*|\\1|"`

> *And this will give me 1234 as a result.* **结果是我会得到1234。**

*You could do the same with `re.sub` function using the same regex.* **您可以使用相同的正则表达式对`re.sub`函数执行相同的操作。**

>>> re.sub(r'.*AAA(.*)ZZZ.*', r'\1', 'gfgfdAAA1234ZZZuijjk')
    '1234'

*In basic sed, capturing group are represented by `\$..\$` , but in python it was represented by `(..)` .* **在基本sed中，捕获组由`\$..\$` ，但是在python中，捕获组由`(..)`表示。**

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### \#5楼 ###

>>> s = 'gfgfdAAA1234ZZZuijjk'
    >>> start = s.find('AAA') + 3
    >>> end = s.find('ZZZ', start)
    >>> s[start:end]
    '1234'

*Then you can use regexps with the re module as well, if you want, but that's not necessary in your case.* **然后，如果需要，也可以将reexpexp与re模块一起使用，但这在您的情况下不是必需的。**

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### \#6楼 ###

import re
    print re.search('AAA(.*?)ZZZ', 'gfgfdAAA1234ZZZuijjk').group(1)

[How to extract the substring between two markers]: https://oldbug.net/q/jA5L/How-to-extract-the-substring-between-two-markers
[https_stackoom.com_question_jA5L]: https://stackoom.com/question/jA5L/%E5%A6%82%E4%BD%95%E6%8F%90%E5%8F%96%E4%B8%A4%E4%B8%AA%E6%A0%87%E8%AE%B0%E4%B9%8B%E9%97%B4%E7%9A%84%E5%AD%90%E5%AD%97%E7%AC%A6%E4%B8%B2
[Here]: https://stackoverflow.com/questions/2241600/python-regex-r-prefix