std::match_results::operator[]
From cppreference.com
< cpp | regex | match results
| const_reference operator[]( size_type n ) const; |
(since C++11) | |
If n > 0 and n < size(), returns a reference to the std::sub_match representing the part of the target sequence that was matched by the nth captured marked subexpression).
If n == 0, returns a reference to the std::sub_match representing the part of the target sequence matched by the entire matched regular expression.
if n >= size(), returns a reference to a std::sub_match representing an unmatched sub-expression (an empty subrange of the target sequence).
The behavior is undefined unless ready() == true
Parameters
| n | - | integral number specifying which match to return |
Return value
Reference to the std::sub_match representing the specified matched subrange within the target sequence.
Example
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[0] << '\n' << "submatch #1: " << sm[1] << '\n'; std::regex re2("a(a*)b"); std::regex_search(target, sm, re2); std::cout << "entire match: " << sm[0] << '\n' << "submatch #1: " << sm[1] << '\n'; }
Output:
entire match: aaab submatch #1: a entire match: aaab submatch #1: aa
See also
| returns the sequence of characters for the particular sub-match (public member function) |