C#的Dictionary字典

Dictionary

Dictionary可以取代Hashtable了;
有一種新的遍歷方式

foreach(KeyValuePair  kv in dic){}

dictionary練習

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Dictionary字典
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary dic = new Dictionary();
            dic.Add(1, "荊轲");
            dic.Add(2, "聶政");
            dic.Add(3, "專諸");
            dic.Add(4, "要離");
            foreach (int item in dic.Keys)
            {
                Console.WriteLine("{0}對應的值為{1}",item,dic[item]);
            }
            foreach(KeyValuePair pair in dic)
            {
                Console.WriteLine("{0}對應的值為{1}",pair.Key,pair.Value);
            }
            Console.ReadKey();
        }
    }
}

用Dictionary檢測字符出現次數

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Dictionary檢測字母出現次數
{
    class Program
    {
        static void Main(string[] args)
        {
            //檢測字符串"Welcome To China"裡面每個字符出現的次數;
            Dictionary dic = new Dictionary();
            string str = "Welcome To China";
            for (int i = 0; i < str.Length; i++)
            {
                if (str[i]==' ')
                {
                    continue;
                }
                if (dic.ContainsKey((str.ToLower())[i]))
                {
                    dic[(str.ToLower())[i]]++;
                }
                else
                {
                    dic[(str.ToLower())[i]] = 1;
                }
            }
            foreach (KeyValuePair item in dic)
            {
                Console.WriteLine("{0}出現過{1}次",item.Key,item.Value);
            }
            Console.ReadKey();

        }
    }
}