std::regex_iterator
| Defined in header <regex>
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| template< class BidirIt, |
(since C++11) | |
std::regex_iterator is a read-only iterator that accesses the individual matches of a regular expression within the underlying character sequence. It meets the requirements of a LegacyForwardIterator, except that for dereferenceable values a and b with a == b, *a and *b will not be bound to the same object.
On construction, and on every increment, it calls std::regex_search and remembers the result (that is, saves a copy of the std::match_results<BidirIt> value). The first object may be read when the iterator is constructed or when the first dereferencing is done. Otherwise, dereferencing only returns a copy of the most recently obtained regex match.
The default-constructed std::regex_iterator is the end-of-sequence iterator. When a valid std::regex_iterator is incremented after reaching the last match (std::regex_search returns false), it becomes equal to the end-of-sequence iterator. Dereferencing or incrementing it further invokes undefined behavior.
A typical implementation of std::regex_iterator holds the begin and the end iterators for the underlying sequence (two instances of BidirIt), a pointer to the regular expression (const regex_type*), the match flags (std::regex_constants::match_flag_type), and the current match (std::match_results<BidirIt>).
Contents |
[edit] Type requirements
-BidirIt must meet the requirements of LegacyBidirectionalIterator.
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[edit] Specializations
Several specializations for common character sequence types are defined:
| Defined in header
<regex> | |
| Type | Definition |
std::cregex_iterator
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std::regex_iterator<const char*> |
std::wcregex_iterator
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std::regex_iterator<const wchar_t*> |
std::sregex_iterator
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std::regex_iterator<std::string::const_iterator> |
std::wsregex_iterator
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std::regex_iterator<std::wstring::const_iterator> |
[edit] Member types
| Type | Definition |
value_type
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std::match_results<BidirIt> |
difference_type
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std::ptrdiff_t |
pointer
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const value_type* |
reference
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const value_type& |
iterator_category
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std::forward_iterator_tag |
iterator_concept (C++20)
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std::input_iterator_tag |
regex_type
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std::basic_regex<CharT, Traits> |
[edit] Data members
| Member | Description |
BidiIt begin (private)
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the begin iterator (exposition-only member object*) |
BidiIt end (private)
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the end iterator (exposition-only member object*) |
const regex_type* pregex (private)
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a pointer to a regular expression (exposition-only member object*) |
regex_constants::match_flag_type flags (private)
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a flag (exposition-only member object*) |
match_results<BidiIt> match (private)
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the current match (exposition-only member object*) |
[edit] Member functions
constructs a new regex_iterator (public member function) | |
| (destructor) (implicitly declared) |
destructs a regex_iterator, including the cached value (public member function) |
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