查找模式前面没有数字的正则表达式匹配

发布于 2025-01-15 17:31:13 字数 475 浏览 4 评论 0原文

我目前正在尝试从字符串中提取日期。以下是一些示例：

02.10 abcdef -> extract '02.10'
abcdef 03.12 -> extract '03.12'
abcdef 308.56 -> extract nothing

一个简单的正则表达式，例如 (\d{2}.\d{2}) 对于前两种情况工作正常，但我在第三个示例中发现了误报，即正则表达式返回 08.56，这是有道理的。

有什么办法可以防止这个字符串被提取吗？我尝试了 [^0-9](\d{2}.\d{2}) ，它似乎在正则表达式调试网站上工作，但当我将其编译为 python 正则表达式时却不起作用，

import re
regex = re.compile(r'[^0-9](\d{2}.\d{2})')

谢谢进步

原文

I am currently trying to extract dates from strings. Here are a few examples:

02.10 abcdef -> extract '02.10'
abcdef 03.12 -> extract '03.12'
abcdef 308.56 -> extract nothing

A simple regex such as (\d{2}.\d{2}) works fine for the first two cases but I catch a false positive for the third example, the regex returns 08.56, which makes sense.

Is there any way to prevent this string from being extracted? I tried [^0-9](\d{2}.\d{2}) which seems to be working on regex debugging websites but not when I compile it as a python regex with

import re
regex = re.compile(r'[^0-9](\d{2}.\d{2})')

Thanks in advance

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不必在意 2025-01-22 17:31:13

我首先认为您需要完整的数字，可以通过以下方式实现：
(\d*\.\d{2}) 返回 308.56

但随后看到了这一行：

有什么办法可以防止该字符串被提取吗？
这让我预计你只需要两个数字，一个点，然后又是两个数字。否则正则表达式不应该返回任何内容。

那么答案应该是：

(?<![\w\d])(\d{2}\.\d{2})(?![\w\d])

您可以在 https://regex101.com/ 上测试它

I First thought you needed the complete number which is possible with:
(\d*\.\d{2}) which returns 308.56

But then is saw the line:

Is there any way to prevent this string from being extracted?
Which made me expect you want only two numbers, a dot and again two numbers. Otherwise the regex should return nothing.

Then the answer should be: