正则表达式查找不包括四位数的数字

问题描述

我想弄清楚如何找到不是年份的数字(我将年份定义为一个四位数宽的数字.)

比如我要接

112123

但不是1234 以避免日期(4 位数字).

如果正则表达式也选择了 12345 那很好，但不是解决这个问题所必需的

(注意:这些要求可能看起来很奇怪.它们是我坚持使用的更大解决方案的一部分)

解决方案

如果lookbehind 和lookahead 可用，以下应该有效:

(?{1,3}|\d{5,})(?!\d)

说明:

(?<!\d) # 前一个字符不是数字(\d{1,3}|\d{5,}) # 1 到 3 之间，或 5 位或更多位，放在第 1 组(?!\d) # 下一个字符不是数字

如果您不能使用环视，以下应该有效:

\b(\d{1,3}|\d{5,})\b

说明:

\b # 字边界(\d{1,3}|\d{5,}) # 1 到 3 之间，或 5 位或更多位，放在第 1 组\b # 词边界

Python 示例:

>>>regex = re.compile(r'(?{1,3}|\d{5,})(?!\d)')>>>regex.findall('1 22 333 4444 55555 1234 56789')['1'、'22'、'333'、'55555'、'56789']

I am trying to figure out how to find numbers that are not years (I'm defining a year as simply a number that is four digits wide.)

For example, I want to pick up

1

12

123

But NOT1234 in order to avoid dates (4 digits).

if the regex also picked up 12345 that is fine, but not necessary for solving this problem

(Note: these requirements may seem odd. They are part of a larger solution that I am stuck with)

解决方案

If lookbehind and lookahead are available, the following should work:

(?<!\d)(\d{1,3}|\d{5,})(?!\d)

Explanation:

(?<!\d)            # Previous character is not a digit
(\d{1,3}|\d{5,})   # Between 1 and 3, or 5 or more digits, place in group 1
(?!\d)             # Next character is not a digit

If you cannot use lookarounds, the following should work:

\b(\d{1,3}|\d{5,})\b

Explanation:

\b                 # Word boundary
(\d{1,3}|\d{5,})   # Between 1 and 3, or 5 or more digits, place in group 1
\b                 # Word boundary

Python example:

>>> regex = re.compile(r'(?<!\d)(\d{1,3}|\d{5,})(?!\d)')
>>> regex.findall('1 22 333 4444 55555 1234 56789')
['1', '22', '333', '55555', '56789']

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