C#中解析复杂日期时间字符串：正则表达式与ParseExact的联合应用

^(Today,)?\s*([A-Z][a-z]{2})\s+([A-Z][a-z]{2,})\s+([0-9]{1,2})\s+([0-9]{4})\s+at\s+([0-9]{2}):([0-9]{2}):([0-9]{2})(?:,\s*(.*))?$

using System;
using System.Globalization;
using System.Text.RegularExpressions;

public class DateTimeParser
{
    public static void Main(string[] args)
    {
        string imperfectDateTimeString = "Today, Fri May 12 2023 at 07:00:00, we go swimming";

        // 定义正则表达式，用于提取日期时间的关键部分
        // 注意：这里使用了更健壮的正则表达式，与上面解析的保持一致
        string pattern = @"^(Today,)?\s*([A-Z][a-z]{2})\s+([A-Z][a-z]{2,})\s+([0-9]{1,2})\s+([0-9]{4})\s+at\s+([0-9]{2}):([0-9]{2}):([0-9]{2})(?:,\s*(.*))?$";

        Match match = Regex.Match(imperfectDateTimeString, pattern);

        if (match.Success)
        {
            // 提取捕获组中的日期和时间信息
            // 捕获组索引：
            // Group[1]: "Today," (可选)
            // Group[2]: "Fri" (星期缩写)
            // Group[3]: "May" (月份缩写)
            // Group[4]: "12" (日期)
            // Group[5]: "2023" (年份)
            // Group[6]: "07" (小时)
            // Group[7]: "00" (分钟)
            // Group[8]: "00" (秒)

            // 构造符合ParseExact格式要求的字符串
            // 格式要求: "dd MMM yyyy HH:mm:ss"
            string day = match.Groups[4].Value;   // "12"
            string month = match.Groups[3].Value; // "May"
            string year = match.Groups[5].Value;  // "2023"
            string hour = match.Groups[6].Value;  // "07"
            string minute = match.Groups[7].Value; // "00"
            string second = match.Groups[8].Value; // "00"

            string cleanedDateTimeString = $"{day} {month} {year} {hour}:{minute}:{second}";
            Console.WriteLine($"提取出的规范日期时间字符串: {cleanedDateTimeString}");

            try
            {
                // 使用DateTime.ParseExact进行精确解析
                DateTime parsedDateTime = DateTime.ParseExact(
                    cleanedDateTimeString,
                    "dd MMM yyyy HH:mm:ss",
                    CultureInfo.InvariantCulture
                );

                Console.WriteLine($"成功解析为DateTime对象: {parsedDateTime}");
                Console.WriteLine($"年份: {parsedDateTime.Year}");
                Console.WriteLine($"月份: {parsedDateTime.Month}");
                Console.WriteLine($"日期: {parsedDateTime.Day}");
                Console.WriteLine($"小时: {parsedDateTime.Hour}");
                Console.WriteLine($"分钟: {parsedDateTime.Minute}");
                Console.WriteLine($"秒钟: {parsedDateTime.Second}");
            }
            catch (FormatException ex)
            {
                Console.WriteLine($"解析失败: {ex.Message}");
            }
            catch (ArgumentNullException ex)
            {
                Console.WriteLine($"参数为空: {ex.Message}");
            }
        }
        else
        {
            Console.WriteLine("未能在字符串中找到匹配的日期时间模式。");
        }

        Console.WriteLine("\n--- 另一个测试案例 ---");
        string anotherString = "Today, Sat Jun 01 2024 at 14:30:15, meeting starts.";
        Match anotherMatch = Regex.Match(anotherString, pattern);
        if (anotherMatch.Success)
        {
            string day = anotherMatch.Groups[4].Value;
            string month = anotherMatch.Groups[3].Value;
            string year = anotherMatch.Groups[5].Value;
            string hour = anotherMatch.Groups[6].Value;
            string minute = anotherMatch.Groups[7].Value;
            string second = anotherMatch.Groups[8].Value;
            string cleanedDateTimeString = $"{day} {month} {year} {hour}:{minute}:{second}";
            Console.WriteLine($"提取出的规范日期时间字符串: {cleanedDateTimeString}");
            try
            {
                DateTime parsedDateTime = DateTime.ParseExact(
                    cleanedDateTimeString,
                    "dd MMM yyyy HH:mm:ss",
                    CultureInfo.InvariantCulture
                );
                Console.WriteLine($"成功解析为DateTime对象: {parsedDateTime}");
            }
            catch (FormatException ex)
            {
                Console.WriteLine($"解析失败: {ex.Message}");
            }
        }
        else
        {
            Console.WriteLine("未能在字符串中找到匹配的日期时间模式。");
        }
    }
}