std::sub_match
Defined in header <regex> |
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(since C++11) |
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.
Type requirements
-BidirIt must meet the requirements of LegacyBidirectionalIterator. |
Specializations
Several specializations for common character sequence types are provided:
Defined in header <regex> |
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| Type | Definition |
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> |
Member types
| Member type | Definition |
|---|---|
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> |
Member objects
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bool matched
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Indicates if this match was successful (public member object) |
Inherited from std::pair
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BidirIt first
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Start of the match sequence. (public member object) |
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BidirIt second
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One-past-the-end of the match sequence. (public member object) |
Member functions
| constructs the match object (public member function) |
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Observers |
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| returns the length of the match (if any) (public member function) |
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| converts to the underlying string type (public member function) |
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| compares matched subsequence (if any) (public member function) |
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Non-member functions
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(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20)
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compares a sub_match with another sub_match, a string, or a character (function template) |
| outputs the matched character subsequence (function template) |
See also
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(C++11)
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iterates through the specified sub-expressions within all regex matches in a given string or through unmatched substrings (class template) |
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