正則表達式

1.基本字符

2.經常使用正則表達式

用戶名	^[a-z0-9_-]{3,16}$
密碼	^[a-z0-9_-]{6,18}$
十六進制值	^#?([a-f0-9]{6}|[a-f0-9]{3})$
電子郵箱	^([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 標籤	^<([a-z]+)([^<]+)*(?:>(.*)<\/\1>|\s+\/>)$
刪除代碼\\註釋	(?<!http:|\S)//.*$
Unicode編碼中的漢字範圍	^[\u2E80-\u9FFF]+$

3.示例

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

// Regex.cpp : 定義控制檯應用程序的入口點。
//

#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:
    判斷一個正則表達式(參數re)是否匹配整個字符序列str,它主要用於驗證文本
    注意，這個正則表達式必須匹配被分析串的所有，不然返回false;若是整個序列被成功匹配，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:
    相似於regex_match,但它不要求整個字符序列徹底匹配
    能夠用regex_search來查找輸入中的一個子序列，該子序列匹配正則表達式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;
    
    //字符串中文替換測試
    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;
}

運行結果：

參考網址：

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

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