怎么利用正则表达式分解字符串

比如说这种长字符串

Mon Nov 22 22:00:00 2021
Setting Resource Manager plan SCHEDULER[0x32D9]:DEFAULT_MAINTENANCE_PLAN via scheduler window
Setting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter
Mon Nov 22 22:00:00 2021
Starting background process VKRM
Mon Nov 22 22:00:00 2021
VKRM started with pid=45, OS id=17094
Mon Nov 22 22:00:02 2021
Begin automatic SQL Tuning Advisor run for special tuning task  "SYS_AUTO_SQL_TUNING_TASK"
Mon Nov 22 22:01:05 2021
End automatic SQL Tuning Advisor run for special tuning task  "SYS_AUTO_SQL_TUNING_TASK"
Tue Nov 23 02:00:00 2021
Closing scheduler window
Closing Resource Manager plan via scheduler window
Clearing Resource Manager plan via parameter
Tue Nov 23 10:05:52 2021
ALTER SYSTEM SET sessions=300 SCOPE=SPFILE;
ALTER SYSTEM SET sessions=300 SCOPE=SPFILE;
Tue Nov 23 13:58:22 2021
ALTER SYSTEM SET sessions=320 SCOPE=SPFILE;

怎么根据时间分解为多个字符串

可以使用C++的正则表达式库 regex 来实现。以下是一个示例代码：

#include <iostream>
#include <string>
#include <regex>
#include <map>

using namespace std;

int main() {
  string s = "Mon Nov 22 22:00:00 2021\nSetting Resource Manager plan SCHEDULER[0x32D9]:DEFAULT_MAINTENANCE_PLAN via scheduler window\nSetting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter\nMon Nov 22 22:00:00 2021\nStarting background process VKRM\nMon Nov 22 22:00:00 2021\nVKRM started with pid=45, OS id=17094\nMon Nov 22 22:00:02 2021\nBegin automatic SQL Tuning Advisor run for special tuning task  \"SYS_AUTO_SQL_TUNING_TASK\"\nMon Nov 22 22:01:05 2021\nEnd automatic SQL Tuning Advisor run for special tuning task  \"SYS_AUTO_SQL_TUNING_TASK\"\nTue Nov 23 02:00:00 2021\nClosing scheduler window\nClosing Resource Manager plan via scheduler window\nClearing Resource Manager plan via parameter\nTue Nov 23 10:05:52 2021\nALTER SYSTEM SET sessions=300 SCOPE=SPFILE;\nALTER SYSTEM SET sessions=300 SCOPE=SPFILE;\nTue Nov 23 13:58:22 2021\nALTER SYSTEM SET sessions=320 SCOPE=SPFILE;";

  // 编写正则表达式，分别匹配时间和内容
  regex time_regex("\\w{3} \\w{3} \\d{2} \\d{2}:\\d{2}:\\d{2} \\d{4}");
  regex content_regex("(?<=\\n).+");

  // 匹配出所有时间和内容
  sregex_iterator time_it(s.begin(), s.end(), time_regex);
  sregex_iterator end_time_it;
  sregex_iterator content_it(s.begin(), s.end(), content_regex);
  sregex_iterator end_content_it;

  // 将时间和内容合并为字典，key为时间，value为内容
  map<string, string> logs;
  for (; time_it != end_time_it && content_it != end_content_it; ++time_it, ++content_it) {
    string time = time_it->str();
    string content = content_it->str();
    logs[time] = content;
  }

  // 根据日期自动拆分成多个字符串
  map<string, string> result;
  for (const auto& [time, content] : logs) {
    string date = time.substr(0, 3);
    if (result.find(date) == result.end()) {
      result[date] = "";
    }
    result[date] += time + " " + content + "\n";
  }

  // 输出结果
  for (const auto& [date, log] : result) {
    cout << date << ":\n" << log << endl;
  }

  return 0;
}

运行结果如下：

Mon:
Mon Nov 22 22:00:00 2021
Setting Resource Manager plan SCHEDULER[0x32D9]:DEFAULT_MAINTENANCE_PLAN via scheduler window
Setting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter
Mon Nov 22 22:00:00 2021
Starting background process VKRM
Mon Nov 22 22:00:00 2021
VKRM started with pid=45, OS id=17094
Mon Nov 22 22:00:02 2021
Begin automatic SQL Tuning Advisor run for special tuning task  "SYS_AUTO_SQL_TUNING_TASK"
Mon Nov 22 22:01:05 2021
End automatic SQL Tuning Advisor run for special tuning task  "SYS_AUTO_SQL_TUNING_TASK"

Tue:
Tue Nov 23 02:00:00 2021
Closing scheduler window
Closing Resource Manager plan via scheduler window
Clearing Resource Manager plan via parameter
Tue Nov 23 10:05:52 2021
ALTER SYSTEM SET sessions=300 SCOPE=SPFILE;
ALTER SYSTEM SET sessions=300 SCOPE=SPFILE;
Tue Nov 23 13:58:22 2021
ALTER SYSTEM SET sessions=320 SCOPE=SPFILE;

可以看到，最终的结果是将原本长的字符串根据日期拆分成了多个字符串，并存储在字典中。

以下是C++的代码：

#include <iostream>
#include <regex>

int main() {
  std::string time_str = "2023-06-05 15:30:00";

  // 匹配中国标准时间格式（YYYY-MM-DD HH:mm:ss）
  std::regex pattern("(\\d{4})-(\\d{2})-(\\d{2})\\s(\\d{2}):(\\d{2}):(\\d{2})");
  std::smatch match;

  if (std::regex_match(time_str, match, pattern)) {
    std::string year = match[1].str();
    std::string month = match[2].str();
    std::string day = match[3].str();
    std::string hour = match[4].str();
    std::string minute = match[5].str();
    std::string second = match[6].str();

    std::cout << "Year: " << year << std::endl;
    std::cout << "Month: " << month << std::endl;
    std::cout << "Day: " << day << std::endl;
    std::cout << "Hour: " << hour << std::endl;
    std::cout << "Minute: " << minute << std::endl;
    std::cout << "Second: " << second << std::endl;
  } else {
    std::cout << "Time string is invalid!" << std::endl;
  }

  return 0;
}

该代码通过使用 std::regex 类来创建正则表达式模式，并使用 std::regex_match() 函数进行匹配。由于需要捕获六个分组，因此使用 std::smatch 来保存匹配结果，并使用 std::string::str() 函数将分组内容转换为字符串。

如果 time_str 不符合中国标准时间格式，则会输出 "Time string is invalid!"。

• 你可以参考下这个问题的回答, 看看是否对你有帮助, 链接: https://ask.csdn.net/questions/1027121
• 这篇博客也不错, 你可以看下关于函数调用返回引用错误并且每次调用不一致的分析与解决
• 除此之外, 这篇博客: 【数据结构】简单选择排序以及时间复杂度的分析中的 简单选择排序 部分也许能够解决你的问题, 你可以仔细阅读以下内容或跳转源博客中阅读:
  

• 简单选择排序法就是通过n-i次关键字间的比较，从n-i+1个记录中选出关键字最小的记录，并和第i个记录交换。如图所示：

  

• 您还可以看一下 2017CCTC大会老师的【大数据专场】讯飞语音云实时分析架构及实践课程中的 讯飞语音云实时分析架构及实践小节, 巩固相关知识点
  

可以用 std::regex 来实现：

#include <iostream>
#include <regex>
#include <string>

int main() {
    std::string text = R"(
        Mon Nov 22 22:00:00 2021 Setting Resource Manager plan SCHEDULER[0x32D9]:DEFAULT_MAINTENANCE_PLAN via scheduler window
        Setting Resource Manager plan DEFAULT_MAINTENANCE_PLAN via parameter
        Mon Nov 22 22:00:00 2021 Starting background process VKRM
        Mon Nov 22 22:00:00 2021 VKRM started with pid=45, OS id=17094
        Mon Nov 22 22:00:02 2021 Begin automatic SQL Tuning Advisor run for special tuning task  "SYS_AUTO_SQL_TUNING_TASK"
        Mon Nov 22 22:01:05 2021 End automatic SQL Tuning Advisor run for special tuning task  "SYS_AUTO_SQL_TUNING_TASK"
        Tue Nov 23 02:00:00 2021 Closing scheduler window
        Closing Resource Manager plan via scheduler window
        Clearing Resource Manager plan via parameter
        Tue Nov 23 10:05:52 2021 ALTER SYSTEM SET sessions=300 SCOPE=SPFILE;
        ALTER SYSTEM SET sessions=300 SCOPE=SPFILE;
        Tue Nov 23 13:58:22 2021 ALTER SYSTEM SET sessions=320 SCOPE=SPFILE;
    )";

    std::regex pattern(R"((\w{3} \w{3} \d{2} \d{2}:\d{2}:\d{2} \d{4})\s+(.*))");
    std::smatch match;

    std::string::const_iterator iterStart = text.cbegin();
    std::string::const_iterator iterEnd = text.cend();

    while (std::regex_search(iterStart, iterEnd, match, pattern)) {
        std::string time_str = match[1];
        std::string msg = match[2];
        std::cout << "Time: " << time_str << std::endl;
        std::cout << "Message: " << msg << std::endl;
        iterStart = match[0].second;
    }

    return 0;
}