正则表达式

Posted 2020-10-24 啊基米舍的博客

1.基本字符

2.常用正则表达式

用户名	^[a-z0-9_-]{3,16}$
密码	^[a-z0-9_-]{6,18}$
十六进制值	^#?([a-f0-9]{6}|[a-f0-9]{3})$
电子邮箱	^([a-z0-9_\\.-]+)@([\\da-z\\.-]+)\\.([a-z\\.]{2,6})$
URL	^(https?:\\/\\/)?([\\da-z\\.-]+)\\.([a-z\\.]{2,6})([\\/\\w \\.-]*)*\\/?$
IP 地址	((2[0-4]\\d|25[0-5]|[01]?\\d\\d?)\\.){3}(2[0-4]\\d|25[0-5]|[01]?\\d\\d?) ^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$
html 标签	^<([a-z]+)([^<]+)*(?:>(.*)<\\/\\1>|\\s+\\/>)$
删除代码\\\\注释	(?<!http:|\\S)//.*$
Unicode编码中的汉字范围	^[\\u2E80-\\u9FFF]+$

3.示例

主要有三大操作：regex_match，regex_search，regex_replace

// Regex.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <regex>  
#include <string>  
#include <vector>  
#include <iostream> 
#include <stdlib.h>

using namespace std;

int test_regex_match()
{
    std::string pattern{ "\\\\d{3}-\\\\d{8}|\\\\d{4}-\\\\d{7}" }; // fixed telephone
    std::regex re(pattern);

    std::vector<std::string> str{ "010-12345678", "0319-9876543", "021-123456789" };

    /* std::regex_match:
    判断一个正则表达式(参数re)是否匹配整个字符序列str,它主要用于验证文本
    注意，这个正则表达式必须匹配被分析串的全部，否则返回false;如果整个序列被成功匹配，返回true
    */

    for (auto tmp : str) {
        bool ret = std::regex_match(tmp, re);
        if (ret) fprintf(stderr, "%s, can match\\n", tmp.c_str());
        else fprintf(stderr, "%s, can not match\\n", tmp.c_str());
    }

    return 0;
}

int test_regex_search()
{
    std::string pattern{ "^((https|http|ftp|rtsp|mms)?:\\/\\/)[^\\s]+" }; // url  
    std::regex re(pattern);

    std::vector<std::string> str{ "http://www.baidu.com", "http://www.cplusplus.com/reference/regex/regex_search/",
        "abcd://124.456", "abcd http://www.cplusplus.com/reference/regex/regex_search/ 123" };

    /* std::regex_search:
    类似于regex_match,但它不要求整个字符序列完全匹配
    可以用regex_search来查找输入中的一个子序列，该子序列匹配正则表达式re
    */

    for (auto tmp : str) {
        bool ret = std::regex_search(tmp, re);
        if (ret) fprintf(stderr, "%s, can search\\n", tmp.c_str());
        else fprintf(stderr, "%s, can not search\\n", tmp.c_str());
    }

    return 0;
}

int test_regex_replace()
{
    // reference: http://www.cplusplus.com/reference/regex/regex_replace/  
    std::string s("there is a subsequence1 in the string\\n");
    std::regex e("\\\\b(sub)([a-z]*)(\\\\d)");   // matches words beginning by "sub"  

    //（1）
    std::cout << std::regex_replace(s, e, "-test-");

    // using string/c-string (3) version:  
    std::cout << std::regex_replace(s, e, "sub-$2-$3");

    // using range/c-string (6) version:  
    std::string result;
    std::regex_replace(std::back_inserter(result), s.begin(), s.end(), e, "$2");
    std::cout << result;

    // with flags:  
    std::cout << std::regex_replace(s, e, "$1 and $2", std::regex_constants::format_no_copy);
    std::cout << std::endl;

    std::cout << std::regex_replace(s, e, "$1 and $2");
    std::cout << std::endl;

    return 0;
}

int _tmain(int argc, _TCHAR* argv[])
{
    regex reg("[0-9]{14}");
    //regex reg("[0-9]{4}[0-9]{2}[0-9]{2}[0-9]{2}[0-9]{2}[0-9]{2}");
    //regex reg("\\\\d{4}\\\\d{2}\\\\d{2}\\\\d{2}\\\\d{2}\\\\d{2}");
    //regex reg("^\\\\d+-");
    smatch sm; 
    string strTest = "1911-20180201111505-1-1";
    if (regex_search(strTest, sm, reg))
    {
        for (int i = 0; i < sm.size(); ++i)
        {
            string str = sm[i];
            cout << str << endl ;
        }

        strTest = sm.suffix().str();
        //cout << strTest << " ";
    }

    cout << endl;
    regex reg2("Windows(?=95|98|NT|2000)");
    strTest = "Windows2000";
    if (regex_search(strTest, sm, reg2))
    {
        for (int i = 0; i < sm.size(); ++i)
        {
            string str = sm[i];
            cout << str << endl;
        }

        strTest = sm.suffix().str();
    }
    cout << endl;
    
    //字符串中文替换测试
    string str = "呃abc";
    str = str.replace(0, 2, "鬼");
    cout << str << endl;
    cout << endl;


    test_regex_match();
    std::cout << std::endl;

    test_regex_search();
    std::cout << std::endl;

    test_regex_replace();
    std::cout << std::endl;

    system("pause");
    return 0;
}

运行结果：

参考网址：

http://tool.oschina.net/uploads/apidocs/jquery/regexp.html

http://www.cplusplus.com/reference/regex/regex_replace/