<regex> 运算符

operator!=
operator>
operator>=
operator<
operator<<
operator<=
operator==

operator!=

比较各对象之间是否不等于。

template <class BidIt>
bool operator!=(const sub_match<BidIt>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator!=(
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator!=(const sub_match<BidIt>& left,
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& right);

template <class BidIt>
bool operator!=(const typename iterator_traits<BidIt>::value_type *left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator!=(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type *right);

template <class BidIt>
bool operator!=(const typename iterator_traits<BidIt>::value_type& left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator!=(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type& right);

template <class BidIt, class Alloc>
bool operator!=(const match_results<BidIt, Alloc>& left,
    const match_results<BidIt, Alloc>& right);

参数

BidIt
迭代器类型。

IOtraits
字符串特征类。

Alloc
allocator 类。

left
要比较的左边的对象。

right
要比较的右边的对象。

注解

各模板运算符返回 !(left == right)。

示例

// std__regex__operator_ne.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

typedef std::cmatch::string_type Mystr;
int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[1];
    std::cout << "match == " << mr.str() << std::endl;
    std::cout << "sub == " << sub << std::endl;
    std::cout << std::endl;

    std::cout << "match != match == " << std::boolalpha
        << (mr != mr) << std::endl;
    std::cout << "sub != sub == " << std::boolalpha
        << (sub != sub) << std::endl;

    std::cout << "string(\"aab\") != sub == " << std::boolalpha
        << (Mystr("aab") != sub) << std::endl;
    std::cout << "sub != string(\"aab\") == " << std::boolalpha
        << (sub != Mystr("aab")) << std::endl;

    std::cout << "\"aab\" != sub == " << std::boolalpha
        << ("aab" != sub) << std::endl;
    std::cout << "sub != \"aab\" == " << std::boolalpha
        << (sub != "aab") << std::endl;

    std::cout << "'a' != sub == " << std::boolalpha
        << ('a' != sub) << std::endl;
    std::cout << "sub != 'a' == " << std::boolalpha
        << (sub != 'a') << std::endl;

    return (0);
    }

match == caaa
sub == aaa

match != match == false
sub != sub == false
string("aab") != sub == true
sub != string("aab") == true
"aab" != sub == true
sub != "aab" == true
'a' != sub == true
sub != 'a' == true

operator<

比较各对象之间是否存在“小于”关系。

template <class BidIt>
bool operator<(const sub_match<BidIt>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator<(
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator<(const sub_match<BidIt>& left,
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& right);

template <class BidIt>
bool operator<(const typename iterator_traits<BidIt>::value_type *left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator<(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type *right);

template <class BidIt>
bool operator<(const typename iterator_traits<BidIt>::value_type& left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator<(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type& right);

参数

BidIt
迭代器类型。

IOtraits
字符串特征类。

Alloc
allocator 类。

left
要比较的左边的对象。

right
要比较的右边的对象。

备注

各模板运算符将其参数转换为字符串类型，并仅当 left 的转换值小于 right 的转换值才返回 ture。

示例

// std__regex__operator_lt.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

typedef std::cmatch::string_type Mystr;
int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[1];
    std::cout << "sub == " << sub << std::endl;
    std::cout << std::endl;

    std::cout << "sub < sub == " << std::boolalpha
        << (sub < sub) << std::endl;

    std::cout << "string(\"aab\") < sub == " << std::boolalpha
        << (Mystr("aab") < sub) << std::endl;
    std::cout << "sub < string(\"aab\") == " << std::boolalpha
        << (sub < Mystr("aab")) << std::endl;

    std::cout << "\"aab\" < sub == " << std::boolalpha
        << ("aab" < sub) << std::endl;
    std::cout << "sub < \"aab\" == " << std::boolalpha
        << (sub < "aab") << std::endl;

    std::cout << "'a' < sub == " << std::boolalpha
        << ('a' < sub) << std::endl;
    std::cout << "sub < 'a' == " << std::boolalpha
        << (sub < 'a') << std::endl;

    return (0);
    }

sub == aaa

sub < sub == false
string("aab") < sub == false
sub < string("aab") == true
"aab" < sub == false
sub < "aab" == true
'a' < sub == true
sub < 'a' == false

operator<<

在流中插入 sub_match。

template <class Elem, class IOtraits, class Alloc, class BidIt>
basic_ostream<Elem, IOtraits>& operator<<(basic_ostream<Elem, IOtraits>& os,
    const sub_match<BidIt>& right);

参数

Elem
元素类型。

IOtraits
字符串特征类。

Alloc
allocator 类。

BidIt
迭代器类型。

os
输出流。

right
要插入的对象。

备注

模板运算符返回 os << right.str()。

示例

// std__regex__operator_ins.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[0];
    std::cout << "whole match: " << sub << std::endl;

    return (0);
    }

whole match: caaa

operator<=

比较各对象之间是否存在“小于”或“等于”关系。

template <class BidIt>
bool operator<=(const sub_match<BidIt>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator<=(
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator<=(const sub_match<BidIt>& left,
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& right);

template <class BidIt>
bool operator<=(const typename iterator_traits<BidIt>::value_type *left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator<=(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type *right);

template <class BidIt>
bool operator<=(const typename iterator_traits<BidIt>::value_type& left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator<=(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type& right);

参数

BidIt
迭代器类型。

IOtraits
字符串特征类。

Alloc
allocator 类。

left
要比较的左边的对象。

right
要比较的右边的对象。

注解

各模板运算符返回 !(right < left)。

示例

// std__regex__operator_le.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

typedef std::cmatch::string_type Mystr;
int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[1];
    std::cout << "sub == " << sub << std::endl;
    std::cout << std::endl;

    std::cout << "sub <= sub == " << std::boolalpha
        << (sub <= sub) << std::endl;

    std::cout << "string(\"aab\") <= sub == " << std::boolalpha
        << (Mystr("aab") <= sub) << std::endl;
    std::cout << "sub <= string(\"aab\") == " << std::boolalpha
        << (sub <= Mystr("aab")) << std::endl;

    std::cout << "\"aab\" <= sub == " << std::boolalpha
        << ("aab" <= sub) << std::endl;
    std::cout << "sub <= \"aab\" == " << std::boolalpha
        << (sub <= "aab") << std::endl;

    std::cout << "'a' <= sub == " << std::boolalpha
        << ('a' <= sub) << std::endl;
    std::cout << "sub <= 'a' == " << std::boolalpha
        << (sub <= 'a') << std::endl;

    return (0);
    }

sub == aaa

sub <= sub == true
string("aab") <= sub == false
sub <= string("aab") == true
"aab" <= sub == false
sub <= "aab" == true
'a' <= sub == true
sub <= 'a' == false

operator==

比较各对象之间是否等于。

template <class BidIt>
bool operator==(const sub_match<BidIt>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator==(
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator==(const sub_match<BidIt>& left,
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& right);

template <class BidIt>
bool operator==(const typename iterator_traits<BidIt>::value_type* left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator==(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type* right);

template <class BidIt>
bool operator==(const typename iterator_traits<BidIt>::value_type& left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator==(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type& right);

template <class BidIt, class Alloc>
bool operator==(const match_results<BidIt, Alloc>& left,
    const match_results<BidIt, Alloc>& right);

参数

BidIt
迭代器类型。

IOtraits
字符串特征类。

Alloc
allocator 类。

left
要比较的左边的对象。

right
要比较的右边的对象。

注解

每个模板运算符将每个参数转换为字符串类型，并比较转换对象是否相等，然后返回相应结果。

当模板运算符将其参数转换为字符串类型时，它会使用以下转换中适用的第一个转换：

通过调用 str 成员函数转换类型为类模板 match_results 或 sub_match 的专用化的参数；

类型为类模板 basic_string 的专用化的参数保持不变；

通过将参数值传递给构造函数，转换所有其他参数类型，以实现适当的类模板 basic_string 的专用化。

示例

// std__regex__operator_eq.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

typedef std::cmatch::string_type Mystr;
int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[1];
    std::cout << "match == " << mr.str() << std::endl;
    std::cout << "sub == " << sub << std::endl;
    std::cout << std::endl;

    std::cout << "match == match == " << std::boolalpha
        << (mr == mr) << std::endl;
    std::cout << "sub == sub == " << std::boolalpha
        << (sub == sub) << std::endl;

    std::cout << "string(\"aab\") == sub == " << std::boolalpha
        << (Mystr("aab") == sub) << std::endl;
    std::cout << "sub == string(\"aab\") == " << std::boolalpha
        << (sub == Mystr("aab")) << std::endl;

    std::cout << "\"aab\" == sub == " << std::boolalpha
        << ("aab" == sub) << std::endl;
    std::cout << "sub == \"aab\" == " << std::boolalpha
        << (sub == "aab") << std::endl;

    std::cout << "'a' == sub == " << std::boolalpha
        << ('a' == sub) << std::endl;
    std::cout << "sub == 'a' == " << std::boolalpha
        << (sub == 'a') << std::endl;

    return (0);
    }

match == caaa
sub == aaa

match == match == true
sub == sub == true
string("aab") == sub == false
sub == string("aab") == false
"aab" == sub == false
sub == "aab" == false
'a' == sub == false
sub == 'a' == false

operator>

比较各对象之间是否存在“大于”关系。

template <class BidIt>
bool operator>(const sub_match<BidIt>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator>(
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator>(const sub_match<BidIt>& left,
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& right);

template <class BidIt>
bool operator>(const typename iterator_traits<BidIt>::value_type *left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator>(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type *right);

template <class BidIt>
bool operator>(const typename iterator_traits<BidIt>::value_type& left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator>(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type& right);

参数

BidIt
迭代器类型。

IOtraits
字符串特征类。

Alloc
allocator 类。

left
要比较的左边的对象。

right
要比较的右边的对象。

注解

各模板运算符返回 right < left。

示例

// std__regex__operator_gt.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

typedef std::cmatch::string_type Mystr;
int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[1];
    std::cout << "sub == " << sub << std::endl;
    std::cout << std::endl;

    std::cout << "sub > sub == " << std::boolalpha
        << (sub > sub) << std::endl;

    std::cout << "string(\"aab\") > sub == " << std::boolalpha
        << (Mystr("aab") > sub) << std::endl;
    std::cout << "sub > string(\"aab\") == " << std::boolalpha
        << (sub > Mystr("aab")) << std::endl;

    std::cout << "\"aab\" > sub == " << std::boolalpha
        << ("aab" > sub) << std::endl;
    std::cout << "sub > \"aab\" == " << std::boolalpha
        << (sub > "aab") << std::endl;

    std::cout << "'a' > sub == " << std::boolalpha
        << ('a' > sub) << std::endl;
    std::cout << "sub > 'a' == " << std::boolalpha
        << (sub > 'a') << std::endl;

    return (0);
    }

sub == aaa

sub > sub == false
string("aab") > sub == true
sub > string("aab") == false
"aab" > sub == true
sub > "aab" == false
'a' > sub == false
sub > 'a' == true

operator>=

比较各对象之间是否存在“大于”或“等于”关系。

template <class BidIt>
bool operator>=(const sub_match<BidIt>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator>=(
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& left,
    const sub_match<BidIt>& right);

template <class BidIt, class IOtraits, class Alloc>
bool operator>=(const sub_match<BidIt>& left,
    const basic_string<typename iterator_traits<BidIt>::value_type, IOtraits, Alloc>& right);

template <class BidIt>
bool operator>=(const typename iterator_traits<BidIt>::value_type *left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator>=(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type *right);

template <class BidIt>
bool operator>=(const typename iterator_traits<BidIt>::value_type& left,
    const sub_match<BidIt>& right);

template <class BidIt>
bool operator>=(const sub_match<BidIt>& left,
    const typename iterator_traits<BidIt>::value_type& right);

参数

BidIt
迭代器类型。

IOtraits
字符串特征类。

Alloc
allocator 类。

left
要比较的左边的对象。

right
要比较的右边的对象。

注解

各模板运算符返回 !(left < right)。

示例

// std__regex__operator_ge.cpp
// compile with: /EHsc
#include <regex>
#include <iostream>

typedef std::cmatch::string_type Mystr;
int main()
    {
    std::regex rx("c(a*)|(b)");
    std::cmatch mr;

    std::regex_search("xcaaay", mr, rx);

    std::csub_match sub = mr[1];
    std::cout << "sub == " << sub << std::endl;
    std::cout << std::endl;

    std::cout << "sub >= sub == " << std::boolalpha
        << (sub >= sub) << std::endl;

    std::cout << "string(\"aab\") >= sub == " << std::boolalpha
        << (Mystr("aab") >= sub) << std::endl;
    std::cout << "sub >= string(\"aab\") == " << std::boolalpha
        << (sub >= Mystr("aab")) << std::endl;

    std::cout << "\"aab\" >= sub == " << std::boolalpha
        << ("aab" >= sub) << std::endl;
    std::cout << "sub >= \"aab\" == " << std::boolalpha
        << (sub >= "aab") << std::endl;

    std::cout << "'a' >= sub == " << std::boolalpha
        << ('a' >= sub) << std::endl;
    std::cout << "sub >= 'a' == " << std::boolalpha
        << (sub >= 'a') << std::endl;

    return (0);
    }

sub == aaa

sub >= sub == true
string("aab") >= sub == true
sub >= string("aab") == false
"aab" >= sub == true
sub >= "aab" == false
'a' >= sub == false
sub >= 'a' == true

另请参阅

<regex>
regex_constants 类
regex_error 类
<regex> 函数
regex_iterator 类
regex_token_iterator 类
regex_traits 类
<regex> typedefs