std::sub_match
<regex>
class sub_match;
The class template std::sub_match is used by the regular expression engine to denote sequences of characters matched by marked sub-expressions.
A match is a [begin, end) pair within the target range matched by the regular expression, but with additional observer functions to enhance code clarity.
Only the default constructor is publicly accessible. Instances of std::sub_match are normally constructed and populated as a part of a std::match_results container during the processing of one of the regex algorithms.
The member functions return defined default values unless the matched member is true.
std::sub_match inherits from std::pair <BidirIt, BidirIt>, although it cannot be treated as a std::pair object because member functions such as assignment will not work as expected.
Contents
[edit] Type requirements
BidirIt must meet the requirements of LegacyBidirectionalIterator.
[edit] Specializations
Several specializations for common character sequence types are provided:
<regex> std::csub_match
std::sub_match<const char*>
std::wcsub_match
std::sub_match<const wchar_t*>
std::ssub_match
std::sub_match<std::string::const_iterator>
std::wssub_match
std::sub_match<std::wstring::const_iterator>
[edit] Nested types
iterator
BidirIt
value_type
std::iterator_traits <BidirIt>::value_type
difference_type
std::iterator_traits <BidirIt>::difference_type
string_type
std::basic_string <value_type>
[edit] Data members
matched(public member object)
Inherited from std::pair
(public member object)
(public member object)
[edit] Member functions
Observers
Modifiers
[edit] Non-member functions
sub_match with another sub_match, a string, or a character (function template) [edit]
[edit] Example
#include <cassert> #include <iostream> #include <regex> #include <string> int main() { std::string sentence{"Friday the thirteenth."}; const std::regex re{"([A-z]+) ([a-z]+) ([a-z]+)"}; std::smatch words; std::regex_search (sentence, words, re); std::cout << std::boolalpha ; for (const auto& m : words) { assert (m.matched); std::cout << "m: [" << m << "], m.length(): " << m.length() << ", " "*m.first: '" << *m.first << "', " "*m.second: '" << *m.second << "'\n"; } }
Output:
m: [Friday the thirteenth], m.length(): 21, *m.first: 'F', *m.second: '.' m: [Friday], m.length(): 6, *m.first: 'F', *m.second: ' ' m: [the], m.length(): 3, *m.first: 't', *m.second: ' ' m: [thirteenth], m.length(): 10, *m.first: 't', *m.second: '.'
[edit] See also
(class template) [edit]