如何从C#中的字符串中获取数字？

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main(string[] args)
    {
        string input = "abc123def456";
        string pattern = @"\d+";
        MatchCollection matches = Regex.Matches(input, pattern);
        foreach (Match match in matches)
        {
            Console.WriteLine(match.Value);
        }
    }
}

using System;

class Program
{
    static void Main(string[] args)
    {
        string input = "abc123def456";
        string result = "";
        foreach (char c in input)
        {
            if (Char.IsDigit(c))
            {
                result += c;
            }
        }
        Console.WriteLine(result);
    }
}