学习C#里的正则表达式

小生初学编程，看了javascript的正则，但很少有介绍c#的。其实和其他语言也差不多，没有啥大同小异

http://msdn.microsoft.com/zh-cn/library/30wbz966(v=VS.85).aspx 这上面讲的不错

首先是单个匹配

    // Create a new Regex object.
    Regex r = new Regex("abc"); 
    // Find a single match in the string.
    Match m = r.Match("123abc456"); 
    if (m.Success) 
    {
        // Print out the character position where a match was found. 
        // (Character position 3 in this case.)
        Console.WriteLine("Found match at position " + m.Index);
        Console.WriteLine("Found:" + m.ToString());

    }

多个匹配，用的是集合类型

    MatchCollection mc;
    String[] results = new String[20];
    int[] matchposition = new int[20];
    
    // Create a new Regex object and define the regular expression.
    Regex r = new Regex("abc"); 
    // Use the Matches method to find all matches in the input string.
    mc = r.Matches("123abc4abcd");
    // Loop through the match collection to retrieve all 
    // matches and positions.
    for (int i = 0; i < mc.Count; i++) 
    {
        // Add the match string to the string array.   
        results[i] = mc[i].Value;
        // Record the character position where the match was found.
        matchposition[i] = mc[i].Index;   
    }