c#高级写法

Linq的参考资料：https://www.cnblogs.com/liqingwen/p/5801249.html

1.判断str字符串中的逗号个数

string str = "1,2,3,4,5,6";
int count = str.Count(ch => ch == ',');

2.使用 where 子句来从数组中筛选那些具有特定长度的字符串

string[] words = { "the", "quick", "brown", "fox", "jumps" };

var query = from word in words
                   where word.Length == 3
                   select word;

foreach (var word in query)
{
     Console.WriteLine(word);
}

3.查询一个List<Dictionary<string, object>>里面的一个值v是否在其里面的字典的值中

        static void Main(string[] args)
        {
            List<Dictionary<string, object>> listDic = new List<Dictionary<string, object>>();

            Dictionary<string, object> dic = new Dictionary<string, object>();
            dic.Add("88", "a");
            dic.Add("123", "b");

            Dictionary<string, object> dic2 = new Dictionary<string, object>();
            dic2.Add("99", "b");

            listDic.Add(dic);
            listDic.Add(dic2);

            //ToDictionary 转换成字典
            var q = listDic.SelectMany(x => x.Where(y => y.Value == "b")).ToDictionary(a =>a.Key, a =>a.Value);

            foreach (var item in q)
            {
                Console.WriteLine(item.Key + "---" + item.Value);
            }

            Console.ReadLine();
        }

 如果需要输出其对应字典在List中的下标，则

        static void Main(string[] args)
        {
            List<Dictionary<string, object>> listDic = new List<Dictionary<string, object>>();
            Dictionary<string, object> dic = new Dictionary<string, object>();
            dic.Add("88", "a");
            dic.Add("123", "b");

            Dictionary<string, object> dic2 = new Dictionary<string, object>();
            dic2.Add("99", "b");

            listDic.Add(dic);
            listDic.Add(dic2);

            //要下标的话，那就只能产生新对象了。
            var q = listDic.Select((x, i) => new
            {
                index = i,
                dict = x.Where(y => y.Value.ToString() == "b")
            });

            foreach (var item in q)
            {
                Console.WriteLine("index:{0}", item.index);
                foreach (var v in item.dict)
                {
                    Console.WriteLine(v.Key + "---" + v.Value);
                }
            }

            Console.ReadLine();
        }

4.字典合并

第一种

chanceAllDic = chanceSmallDic.Concat(chanceBigDic).ToDictionary(k => k.Key, v => v.Value);

第二种

buildDic = BattleJsonData.chanceSmallDic.Union(BattleJsonData.chanceBigDic).ToDictionary(k => k.Key, v => v.Value);

5.类型转换

    public static List<Dictionary<string, object>> ListDicSort(List<object> listDic, string rank)
    {
        List<Dictionary<string, object>> myListDic = new List<Dictionary<string, object>>();
        //普通写法
        //for (int i = 0; i < listDic.Count; i++)
        //{
        //    Dictionary<string, object> o = (Dictionary<string, object>)listDic[i];
        //    myListDic.Add(o);
        //}
        //Linq写法
        myListDic = (from x in listDic select (Dictionary < string,object>)x).ToList();

        return myListDic.OrderByDescending(a => a[rank]).ToList();
    }

6.自动分组

            //============================模拟数据==================================//
            Dictionary<string, Dictionary<string, object>> dic_dic = new Dictionary<string, Dictionary<string, object>>();
            Dictionary<string, object> dic = new Dictionary<string, object>();
            dic.Add("name", "回复剂");
            dic.Add("type", "药");
            dic_dic.Add("0", dic);
            Dictionary<string, object> dic2 = new Dictionary<string, object>();
            dic2.Add("name", "以太");
            dic2.Add("type", "药");
            dic_dic.Add("1", dic2);
            Dictionary<string, object> dic3 = new Dictionary<string, object>();
            dic3.Add("name", "斧子");
            dic3.Add("type", "武器");
            dic_dic.Add("2", dic3);
            Dictionary<string, object> dic4 = new Dictionary<string, object>();
            dic4.Add("name", "斧子");
            dic4.Add("type", "药");
            dic_dic.Add("3", dic4);
            //===================================================================//

            //按照type类型进行分类并且生成出字典嵌套字典
            Dictionary<string, List<Dictionary<string, object>>> allDic = dic_dic.GroupBy(x => x.Value["type"])
                                                                       .Select(g => new { key = g.Key, value = g.Select(s => s.Value) })
                                                                        .ToDictionary(v => v.key.ToString(), v => v.value.ToList());