std::regex_search

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)

确定正则表达式之间是否匹配。e以及目标字符序列中的一些子序列。

1%29分析泛型范围[first,last)中返回匹配结果m...

2%29分析以空结尾的字符串。str中返回匹配结果m...

3%29分析字符串s中返回匹配结果m...

4-6%29等于%281-3%29，只是省略了匹配结果.

7%29重载3被禁止接受临时字符串，否则此函数填充匹配。[医]结果：m与字符串迭代器一起，这些迭代器立即失效。

regex_search将成功匹配给定序列的任何子序列，而std::regex_match只会回来true如果正则表达式与全顺序。

参数

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

类型要求

-Bidirit必须符合双向迭代器的要求。

-分配器必须符合分配器的要求。

返回值

回报true如果有匹配，false否则。在任何一种情况下，对象m更新如下：

如果不存在匹配：

m就绪%28%29==真

*。

空%28%29==真

M.尺寸%28%29=0

如果存在匹配：

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	m0.first
m.prefix().matched	m.prefix().first != m.prefix().second
m.suffix().first	m0.second
m.suffix().second	last
m.suffix().matched	m.suffix().first != m.suffix().second
m0.first	the start of the matching sequence
m0.second	the end of the matching sequence
m0.matched	true
mn.first	the start of the sequence that matched marked sub-expression n, or last if the subexpression did not participate in the match
mn.second	the end of the sequence that matched marked sub-expression n, or last if the subexpression did not participate in the match
mn.matched	true if sub-expression n participated in the match, false otherwise

注记

为了检查目标序列中的所有匹配，std::regex_search可以在循环中调用，每次从m[0].second之前的电话。std::regex_iterator为这个迭代提供了一个简单的接口。

例

二次

#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})");
 
    // simple match
    for (const auto &line : lines) {
        std::cout << line << ": " << std::boolalpha
                  << std::regex_search(line, color_regex) << '\n';
    }   
    std::cout << '\n';
 
    // show contents of marked subexpressions within each match
    std::smatch color_match;
    for (const auto& line : lines) {
        if(std::regex_search(line, color_match, color_regex)) {
            std::cout << "matches for '" << line << "'\n";
            std::cout << "Prefix: '" << color_match.prefix() << "'\n";
            for (size_t i = 0; i < color_match.size(); ++i) 
                std::cout << i << ": " << color_match[i] << '\n';
            std::cout << "Suffix: '" << color_match.suffix() << "\'\n\n";
        }
    }
 
    // repeated search (see also std::regex_iterator)
    std::string log(R"(
        Speed:        366
        Mass:        35
        Speed:        378
        Mass:        32
        Speed:        400
        Mass:        30)");
    std::regex r(R"(Speed:\t\d*)");
    std::smatch sm;
    while(regex_search(log, sm, r))
    {
        std::cout << sm.str() << '\n';
        log = sm.suffix();
    }
 
    // C-style string demo
    std::cmatch cm;
    if(std::regex_search("this is a test", cm, std::regex("test"))) 
        std::cout << "\nFound " << cm[0] << " at position " << cm.prefix().length();
}

二次

产出：

二次

Roses are #ff0000: true
violets are #0000ff: true
all of my base are belong to you: false
 
matches for 'Roses are #ff0000'
Prefix: 'Roses are '
0: #ff0000
1: ff
2: 00
3: 00
Suffix: ''
 
matches for 'violets are #0000ff'
Prefix: 'violets are '
0: #0000ff
1: 00
2: 00
3: ff
Suffix: ''
 
Speed:        366
Speed:        378
Speed:        400
 
Found test at position 10

二次

另见

basic_regex (C++11)	regular expression object (class template)
match_results (C++11)	identifies one regular expression match, including all sub-expression matches (class template)
regex_match (C++11)	attempts to match a regular expression to an entire character sequence (function template)

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最后更新于：2017-12-18