std::match_results::str(3)

Hey bestie 💖 welcome to the std::match_results::str(3) page from the C++ Standard Libary manual (yes, spelled exactly like that, no cap). This is the iconic little member that hands you back a match as a string. Let’s get into it 🎀

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💖 NAME 💖

std::match_results::str — std::match_results::str

yes bestie, the NAME section really said that twice 😭 iconic behavior

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✨ Synopsis ✨

Okay so here’s the signature, literally:

string_type str( size_type n = 0 ) const;  (since C++11)

It returns a string representing the indicated sub-match 🫶

• If n == 0, you get a string representing the entire matched expression. the whole thing, main character energy.
• If 0 < n && n < size(), you get a string representing the n^th sub-match. sub-match moment.
• If n >= size(), you get a string representing the unmatched match. no cap, that’s what it says.

The call is equivalent to string_type((*this)[n]); — that’s the whole vibe 🔥

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🎀 Parameters 🎀

• n — an integral number specifying which match to return.

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🌸 Return value 🌸

Returns a string representing the specified match or sub match. slay

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🦋 Example 🦋

Run this code, bestie:

// Run this code

#include <iostream>
#include <regex>
#include <string>

int main()
{
    std::string target("baaaby");
    std::smatch sm;

    std::regex re1("a(a)*b");
    std::regex_search(target, sm, re1);
    std::cout << "entire match: " << sm.str(0) << '\n'
              << "submatch #1: " << sm.str(1) << '\n';

    std::regex re2("a(a*)b");
    std::regex_search(target, sm, re2);
    std::cout << "entire match: " << sm.str(0) << '\n'
              << "submatch #1: " << sm.str(1) << '\n';
}

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💜 Output 💜

entire match: aaab
submatch #1: a
entire match: aaab
submatch #1: aa

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👑 See also 👑

• operator[] — returns specified sub-match (public member function). iykyk

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xoxo, your regex bestie 💖 — source: http://cppreference.com, dated 2024.06.10.