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std::sub_match<BidirIt>:: operator string_type, std::sub_match<BidirIt>:: str

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std::sub_match
Member functions
sub_match::str sub_match::operator string_type
Non-member functions
(until C++20) (until C++20) (until C++20) (until C++20) (until C++20) (C++20)
operator string_type ( ) const ;
(1)
string_type str ( ) const ;
(2)

转换为底层 std::basic_string 类型的对象。

1) 隐式转换。
2) 显式转换。

返回值

作为底层 std::basic_string 类型的匹配字符序列对象。若 matched 成员为 false ，则返回空字符串。

复杂度

与底层字符序列的长度呈线性关系。

示例

运行此代码 
#include <cassert>
#include <iostream>
#include <regex>
#include <string>
int main()
{
    const std::string html{R"("<a href="https://cppreference.net/">)"};
    const std::regex re{"(http|https|ftp)://([a-z]+)\\.([a-z]{3})"};
    std::smatch parts;
    std::regex_search(html, parts, re);
    for (std::ssub_match const& sub : parts)
    {
        const std::string s = sub; // (1) 隐式转换
        assert(s == sub.str());    // (2)
        std::cout << s << '\n';
    }
}

输出： 

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