正则表达式 C++：从字符串中提取子字符串，然后计算每个单词答案

【问题标题】：Regex C++: extract substring from a string then count each word正则表达式 C++：从字符串中提取子字符串，然后计算每个单词
【发布时间】：2015-02-17 17:39:00
【问题描述】：

我有以下格式的文本字符串。

*tag0 hi how are you tag1 where are you from tag3 i would like to eat some food*

文本位于向量中，我将其分配给变量字符串line2。我想从每个标签中提取单词并将其计为令牌。下面是我的代码。

smatch t_headermatch;
regex re("tag[0-9]+");

for (int i = 0; i < (int)boxraw.size(); ++i) {          
    line2 = boxraw.at(i); 

while (regex_search(line2, t_headermatch, re)){
        for (auto x : t_headermatch)cout << x << " ";

//If find tag header, print the words after the header and count it as token.

//repeat the process until found a new tag header.exit if no tag found


        cout <<endl;
        line2 = t_headermatch.suffix().str();
    }

我的预期输出如下所示：

Found 3 tag

tag0
hi token 1
how token 2
are token 3
you token 4
tag1
where 1 
are  2 
you 3
tag3 
i 1
would 2
like 3
to 4
eat 5
some 6
food 7

【问题讨论】：

标签： c++ regex substring extract

【解决方案1】：

使用下面的正则表达式

"tag\\d+((?:\\s+(?!tag)\\w+)+)"

每个regex_search 都会返回match_result 对象

t_headermatch[0] : the whole match, i.e. "tag0 hi how are you"
t_headermatch[1] : the substring with tokens "hi how are you"

你还需要拆分令牌等。

【讨论】：