实现正则表达式奇偶数字符串匹配

Question

string input = @"scf{0}dhf{1}do{2}vsf{3}pp{4}";
            Regex regex = new Regex(@"(?<val>{\d+})", RegexOptions.Multiline);
 
            MatchCollection matches = regex.Matches(input);
            for(int i = 0; i < matches.Count; i++)
            {
                if(i % 2 == 0) Console.Write(matches[i].Groups["val"].Value+",");
            }

Answer 1

 string input = @"scf{0}dhf{{1}}do{{{2}}}vsf{{{{3}}}}pp{{{{{4}}}}}";
            var list = Regex.Matches(input, @"[{]+\d+[}]+").OfType<Match>().Select(t => t.Value).Where(t=>Regex.IsMatch(Regex.Replace(t,"{{|}}",""),@"^{\d+}$")).ToList();
            list.ForEach(t=>Console.WriteLine(t));

Answer 2

两边的括号数量确定相等吗？如果是这样呢？
String str="{{{{{12}}}";
str="{{{{12}}}}}";

Answer 3

两边的括号数量确定相等吗？如果是这样呢？
String str="{{{{{12}}}";
str="{{{{12}}}}}";

2边不一定相等，只要是奇数才有效

Answer 4

http://bbs.csdn.net/topics/390708966?page=1#post-396750286