Difference between revisions of "cpp/regex/regex search"
m (Use since= and until= params of {{dcl}} template.) |
(lwg 2329) |
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| Line 54: | Line 54: | ||
std::regex_constants::match_flag_type flags = | std::regex_constants::match_flag_type flags = | ||
std::regex_constants::match_default ); | std::regex_constants::match_default ); | ||
| + | }} | ||
| + | {{dcl | num=7 | since=c++14 | 1= | ||
| + | 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; | ||
}} | }} | ||
{{dcl end}} | {{dcl end}} | ||
| Line 66: | Line 78: | ||
@4-6@ Equivalent to (1-3), just omits the match results. | @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. | ||
{{tt|regex_search}} will successfully match any subsequence of the given sequence, whereas {{lc|std::regex_match}} will only return {{c|true}} if the regular expression matches the ''entire'' sequence. | {{tt|regex_search}} will successfully match any subsequence of the given sequence, whereas {{lc|std::regex_match}} will only return {{c|true}} if the regular expression matches the ''entire'' sequence. | ||
Revision as of 11:41, 22 March 2014
| Defined in header <regex>
|
||
| template< class BidirIt, class Alloc, class CharT, class Traits > |
(1) | (since C++11) |
| template< class Alloc, class CharT, class Traits > bool regex_search( const CharT* str, |
(2) | (since C++11) |
| template< class STraits, class SAlloc, class Alloc, class CharT, class Traits > |
(3) | (since C++11) |
| template< class BidirIt, class CharT, class Traits > |
(4) | (since C++11) |
| template< class CharT, class Traits > bool regex_search( const CharT* str, |
(5) | (since C++11) |
| template< class STraits, class SAlloc, class CharT, class Traits > |
(6) | (since C++11) |
| template< class STraits, class SAlloc, class Alloc, class CharT, class Traits > |
(7) | (since C++14) |
Determines if there is a match between the regular expression e and some subsequence in the target character sequence.
[first,last). Match results are returned in m.str. Match results are returned in m.s. Match results are returned in m.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.
Contents |
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 | ||
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 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 if a match was found, false otherwise |
| m[n].first | the start of the sequence that matched sub-expression n, or last if the subexpression did not participate in the match
|
| m[n].second | the end of the sequence that matched 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 |
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::ssub_match sub_match = color_match[i]; std::string sub_match_str = sub_match.str(); std::cout << i << ": " << sub_match_str << '\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) |
