如何在正则表达式模式中定义循环？

Question

I want to assert that a String contains two identical subStrings. 我想断言一个字符串包含两个相同的子字符串。

I tried this regex: [A-ZA-Z]{2} 我尝试过此正则表达式： [A-ZA-Z]{2}

What I want to detect: 我要检测的是：

AZAZ
CUCU
PIPI

But this regex just checks if there are 4 uppercased Letters in a row, so 但是此正则表达式仅检查连续是否有4个大写字母，因此

ABCD --> it's good and it shouldn't be

I'm really sorry if this is unclear, I don't get how to write the regex to assert repetitions. 如果还不清楚，我真的很抱歉，我不知道如何编写正则表达式来断言重复。

Answer 1

With Python you can do the following: 使用Python，您可以执行以下操作：

p="((?P<two_chars>[A-Z]{2})(?P=two_chars))"
s="AZAZABCDCUCUPIPI"
re.findall(p, s)
[('AZAZ', 'AZ'), ('CUCU', 'CU'), ('PIPI', 'PI')]

and then extract from the list the elements you want. 然后从列表中提取所需的元素。 Or you can be faster and do: 或者，您可以更快地执行以下操作：

[k for k,v in re.findall(p,s)]
['AZAZ', 'CUCU', 'PIPI']

Hope it helps. 希望能帮助到你。