| Defined in header <regex> | ||
|---|---|---|
template< class BidirIt,
class Alloc, class CharT, class Traits >
bool regex_search( BidirIt first, BidirIt last,
std::match_results<BidirIt,Alloc>& m,
const std::basic_regex<CharT,Traits>& e,
std::regex_constants::match_flag_type flags =
std::regex_constants::match_default ); | (1) | (since C++11) |
template< class CharT, class Alloc, class Traits >
bool regex_search( const CharT* str,
std::match_results<const CharT*,Alloc>& m,
const std::basic_regex<CharT,Traits>& e,
std::regex_constants::match_flag_type flags =
std::regex_constants::match_default ); | (2) | (since C++11) |
template< class STraits, class SAlloc,
class Alloc, class CharT, class Traits >
bool regex_search( const std::basic_string<CharT,STraits,SAlloc>& s,
std::match_results<
typename std::basic_string<CharT,STraits,SAlloc>::const_iterator,
Alloc
>& m,
const std::basic_regex<CharT, Traits>& e,
std::regex_constants::match_flag_type flags =
std::regex_constants::match_default ); | (3) | (since C++11) |
template< class BidirIt,
class CharT, class Traits >
bool regex_search( BidirIt first, BidirIt last,
const std::basic_regex<CharT,Traits>& e,
std::regex_constants::match_flag_type flags =
std::regex_constants::match_default ); | (4) | (since C++11) |
template< class CharT, class Traits >
bool regex_search( const CharT* str,
const std::basic_regex<CharT,Traits>& e,
std::regex_constants::match_flag_type flags =
std::regex_constants::match_default ); | (5) | (since C++11) |
template< class STraits, class SAlloc,
class CharT, class Traits >
bool regex_search( const std::basic_string<CharT,STraits,SAlloc>& s,
const std::basic_regex<CharT,Traits>& e,
std::regex_constants::match_flag_type flags =
std::regex_constants::match_default ); | (6) | (since C++11) |
template< class STraits, class SAlloc,
class Alloc, class CharT, class Traits >
bool regex_search( const std::basic_string<CharT,STraits,SAlloc>&&,
std::match_results<
typename std::basic_string<CharT,STraits,SAlloc>::const_iterator,
Alloc
>&,
const std::basic_regex<CharT, Traits>&,
std::regex_constants::match_flag_type flags =
std::regex_constants::match_default ) = delete; | (7) | (since C++14) |
Determines if there is a match between the regular expression e and some subsequence in the target character sequence.
1) Analyzes generic range
[first,last). Match results are returned in m. 2) Analyzes a null-terminated string pointed to by
str. Match results are returned in m. 3) Analyzes a string
s. Match results are returned in m. 4-6) Equivalent to (1-3), just omits the match results.
7) The overload 3 is prohibited from accepting temporary strings, otherwise this function populates match_results m with string iterators that become invalid immediately.
regex_search will successfully match any subsequence of the given sequence, whereas std::regex_match will only return true if the regular expression matches the entire sequence.
Parameters
| first, last | - | a range identifying the target character sequence |
| str | - | a pointer to a null-terminated target character sequence |
| s | - | a string identifying target character sequence |
| e | - | the std::regex that should be applied to the target character sequence |
| m | - | the match results |
| flags | - | std::regex_constants::match_flag_type governing search behavior |
| Type requirements | ||
- BidirIt must meet the requirements of BidirectionalIterator. | ||
- Alloc must meet the requirements of Allocator. | ||
Return value
Returns true if a match exists, false otherwise. In either case, the object m is updated, as follows:
If the match does not exist:
m.ready() == true | |
m.empty() == true | |
m.size() == 0 |
If the match exists:
m.ready() | true |
m.empty() | false |
m.size() | number of marked subexpressions plus 1, that is, 1+e.mark_count() |
m.prefix().first | first |
m.prefix().second | m[0].first |
m.prefix().matched | m.prefix().first != m.prefix().second |
m.suffix().first | m[0].second |
m.suffix().second | last |
m.suffix().matched | m.suffix().first != m.suffix().second |
m[0].first | the start of the matching sequence |
m[0].second | the end of the matching sequence |
m[0].matched | true |
m[n].first | the start of the sequence that matched marked sub-expression n, or last if the subexpression did not participate in the match |
m[n].second | the end of the sequence that matched marked sub-expression n, or last if the subexpression did not participate in the match |
m[n].matched | true if sub-expression n participated in the match, false otherwise |
Notes
In order to examine all matches within the target sequence, std::regex_search may be called in a loop, restarting each time from m[0].second of the previous call. std::regex_iterator offers an easy interface to this iteration.
Example
#include <iostream>
#include <string>
#include <regex>
int main()
{
std::string lines[] = {"Roses are #ff0000",
"violets are #0000ff",
"all of my base are belong to you"};
std::regex color_regex("#([a-f0-9]{2})"
"([a-f0-9]{2})"
"([a-f0-9]{2})");
for (const auto &line : lines) {
std::cout << line << ": "
<< std::regex_search(line, color_regex) << '\n';
}
std::smatch color_match;
for (const auto &line : lines) {
std::regex_search(line, color_match, color_regex);
std::cout << "matches for '" << line << "'\n";
for (size_t i = 0; i < color_match.size(); ++i)
std::cout << i << ": " << color_match[i] << '\n';
}
}Output:
Roses are #ff0000: 1 violets are #0000ff: 1 all of my base are belong to you: 0 matches for 'Roses are #ff0000' 0: #ff0000 1: ff 2: 00 3: 00 matches for 'violets are #0000ff' 0: #0000ff 1: 00 2: 00 3: ff matches for 'all of my base are belong to you'
See also
| (C++11) | regular expression object (class template) |
| (C++11) | identifies one regular expression match, including all sub-expression matches (class template) |
| (C++11) | attempts to match a regular expression to an entire character sequence (function template) |
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