正则表达式匹配未用数字括起来的 5 位子字符串 [英] Regex matching 5-digit substrings not enclosed with digits

问题描述

我想从字符串中提取 5 个连续的数字

I want to extract 5 continuous digits from the string

我写的代码.

re.findall(r"((\D|^)*)\d\d\d\d\d((\D|$)*)", s)

但它不能传递字符串

"Helpdesk-Agenten (m/w) Kennziffer: 12966"

预期结果是:

12966

示例 2:

#input
"Helpdesk-Agenten (m/w) Kennziffer: 12966abc"
# expected
12966

示例 3:

#input
"Helpdesk-Agenten (m/w) Kennziffer: 12966345"
# expected
"" (because the length of continuous digits is longer than 5)

推荐答案

你当前的正则表达式 (((\D|^)*)\d\d\d\d\d((\D|$)*)) 与 re.findall 一起使用不会返回数字块，因为它们没有被捕获.更多，(\D|^)* 和(\D|$)* 部分是可选，这意味着他们没有做他们应该做的事情，正则表达式会在更长的数字块中找到 5 位块.

Your current regex (((\D|^)*)\d\d\d\d\d((\D|$)*)) used with re.findall won't return the digit chunks because they are not captured. More, the (\D|^)* and (\D|$)* parts are optional and that means they do not do what they are supposed to do, the regex will find 5 digit chunks inside longer digits chunks.

如果你必须找到没有被其他数字包围的5位数字块，使用

If you must find 5 digit chunk not enclosed with other digits, use

re.findall(r"(?<!\d)\d{5}(?!\d)", s)

查看正则表达式演示

详情:

• (? - 当前位置之前不允许有数字
• \d{5} - 5 位数字
• (?!\d) - 当前位置后不允许有数字.

• (?<!\d) - no digit is allowed before the current location
• \d{5} - 5 digits
• (?!\d) - no digit allowed after the current location.

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