正则匹配

最新推荐文章于 2021-08-26 10:00:55 发布

转载最新推荐文章于 2021-08-26 10:00:55 发布 · 83 阅读

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/huhusw/p/10884326.html

此博客展示了C++中正则表达式的使用。包含regex_match匹配整个字符串、regex_search查找匹配项，还介绍了使用iterator和token_iterator返回多个匹配结果，以及子表达式匹配。通过多个示例代码，如对日期、IP地址、身份证号的匹配，展示了正则表达式在C++中的应用。

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#include <iostream>
#include <string>
#include <regex>
using namespace std;

int main()
{
//regex_match匹配整个字符串
//reg1匹配大小写字母,不能匹配空格
regex reg1("\\w+day");
smatch r1;
string s1 = "Sat123urdayday";
cout << boolalpha << regex_match(s1,r1,reg1) << endl; //true
cout << "s1匹配结果：" << r1.str() << endl;

//regex_match只返回第一个匹配结果
//string s2 = "saturday and sunday"; //false
string s2 = "saturaday ndsunday"; //true
smatch r2;
cout << boolalpha << regex_match(s2, r2, reg1) << endl; //false
cout << "s2匹配结果：" << r2.str() << " 1234654" << endl; //结果为空

smatch rr1;
smatch rr2;
cout << boolalpha << regex_search(s1, rr1, reg1) << endl;
cout << "s1匹配结果：" << rr1.str() << endl;
cout << boolalpha << regex_search(s2, rr2, reg1) << endl;
cout << "s2匹配结果：" << rr2.str() << " asdasd5" << endl;
cout << endl;

//使用iterator返回多个匹配结果
//结果要用->
cout << "iterator结果：" << endl;
sregex_iterator it(s2.begin(), s2.end(), reg1);
sregex_iterator end;
for(; it != end; ++it)
{
cout << it->str() << endl;
//cout << *it << endl; 错误
}

cout << "token_iterator结果：" << endl;
sregex_token_iterator tit(s2.begin(), s2.end(), reg1);
sregex_token_iterator tend;
for(; tit != tend; ++tit)
{
cout << tit->str() << endl;
cout << *tit << endl;
}

//子表达式匹配
regex reg2("(\\d{1,3}):(\\d{1,3}):(\\d{1,3}):(\\d{1,3})");
string ip = "0:11:222:333";
smatch m;
regex_match(ip, m, reg2);
cout << "输出：str()" << endl;
cout << m.str() << endl;
cout << m.str(1) << endl;
cout << m.str(2) << endl;
cout << m.str(3) << endl;
cout << m.str(4) << endl;

cout << "输出：[i]" << endl;
cout << m[0] << endl;
cout << m[1] << endl;
cout << m[2] << endl;
cout << m[3] << endl;
cout << m[4] << endl;

//输出结果同上
//regex_search(ip, m, str2);
cout << endl;
string ip2 = "0:11:222:333 4:55:66:7";
sregex_iterator ip_it(ip2.begin(), ip2.end(), reg2);
sregex_iterator ip_end;
for(; ip_it != ip_end; ++ip_it)
{
cout << ip_it->str() << endl;
cout << ip_it->str(1) << endl;
cout << ip_it->str(2) << endl;
cout << ip_it->str(3) << endl;
cout << ip_it->str(4) << endl;
}

regex regx("\\d{18}");
regex regx1("\\d{17}+[X]");
smatch sma;
string str = "41282519980203733X";
cout << boolalpha << regex_match(str,sma,regx1) << endl; //true
cout << "s1匹配结果：" << sma.str() << endl;

return 0;

}

转载于:https://www.cnblogs.com/huhusw/p/10884326.html