c++ - 相同分隔符之间的多个子字符串

Question

我是 C++ 的新手，想知道如何从单个字符串中的相同分隔符之间提取多个子字符串？

例如

"{("id":"4219","firstname":"Paul"),("id":"4349","firstname":"Joe"),("id":"4829","firstname":"Brandy")}"

我想要 ids:

4219 , 4349 , 4829

Answer 1

您可以使用正则表达式来匹配 ID:

#include <iostream>
#include <regex>

int main() {
    // This is your string.
    std::string s{ R"({("id":"4219","firstname":"Paul"),("id":"4349","firstname":"Joe"),"("id":"4829","firstname":"Brandy")})"};

    // Matches "id":"<any number of digits>"
    // The id will be captured in the first group
    std::regex r(R"("id"\s*:\s*"(\d+))");

    // Make iterators that perform the matching
    auto ids_begin = std::sregex_iterator(s.begin(), s.end(), r);
    auto ids_end = std::sregex_iterator();

    // Iterate the matches and print the first group of each of them
    // (where the id is captured)
    for (auto it = ids_begin; it != ids_end; ++it) {
        std::smatch match = *it;
        std::cout << match[1].str() << ',';
    }

}

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