正则表达式为非连续大写小写 [英] Regex for non-consecutive uppercase with lowercase

问题描述

std :: string s（AAA）;

std :: smatch m;

std :: regex e（（？=。{3， } [AZ]）（？=。{0，} [az]）。*）;

output = std :: regex_search（s，m，e）;



这里它应该有3个或更多的大写字母和零个或多个小写字母。

然而输出为零意味着它失败。当我尝试用1替换零和

s（AAA4）时它工作正常。



所以现在我希望它允许零或更多，但似乎它不接受零

我甚至尝试量词（*）相当于{0，}仍然不起作用。



我尝试过：



。

我也试过[AZ] {3，} [az ] * 
但这将允许：
s（AAA）和s（AAAb）但现在是s（AbAA）
，因为只有当鞋帮连续时才允许。 / pre> 
解决方案
 
您需要添加字符串代码的开头和结尾。
 
试试这个：
 
 
 ^ [AZ] {3，} [az] * 
 
 
 

你的正则表达式需要两个未被捕获的后缀，这很奇怪。



获取 Expresso [ ^ ] - 免费，它检查并生成正则表达式。

std::string s("AAA");
std::smatch m;
std::regex e("(?=.{3,}[A-Z])(?=.{0,}[a-z]).*");
output = std::regex_search(s, m, e);

Here it should have 3 or more uppercase letters and zero or more lowercase letter.
However the output is zero meaning it fails. When I try replace zero with 1 and
s("AAA4") it works fine.

So now I want it to allow zero or more but it seems like it is not accepting zero
I even tried quantifier (*) which is equivalent to {0,} still not working.

What I have tried:

.

I also tried [A-Z]{3,}[a-z]* 
but this will allow:
s("AAA") and s("AAAb") but now s("AbAA")
as it will allow only if upper are consecutive.

解决方案

You need to add the start and end of string codes.
Try this:

^[A-Z]{3,}[a-z]*

Your Regex requires two suffixes which aren't captured, which is rather odd.

Get a copy of Expresso[^] - it's free, and it examines and generates Regular expressions.

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