学习笔记3 下午 字符串

 

字符串: 是一系列Unicode字符，一个字符数组
char char ='1';
string str = "abc";  //一系列Unicode字符，一个字符数组
相当于:  char[] str = new char[]{'a','b','c'};

另一种 初始化字符串
string str = new string(new char[] { 'a','b','c'});

字符串的基本方法：
string str = " abc ";
str.TrimStart()
str.TrimEnd()
str.Trim()

char.IsDigit(char c)
char.IsDigit(string s,int index)
char.IsWhiteSpace(char c)
char.IsWhiteSpace(string s,int index)

str.Replace(old,new)
str.Substring(int startIndex)
str.Substring(int startIndex, int Length)

str.Contains(string/char) //是否包含
str.IndexOf(string/char)  //第一次出现的位置,找不到为 -1

str.ToUpper();
str.ToLower();

str.Split('|');
str.Split(new char[] { '*', '|', '#' });

str.Remove(int startIndex)
str.Remove(int startIndex,int Count);
str.Insert(int startIndex,string value)
....

练习： 身份证题目
Int32.Parse(string) // 将字符串解析为 Int32类型
string k = "12";
int n = 10;
int r = n + Int32.Parse(k);
Console.WriteLine(r);

随机发生器 System.Random
Random rdm = new Random();
Random rdm = new Random(int Seed); 
//只要种子一样，运行产生的也一定一样。
//所以可以放入如时间，秒等伪种子,别再循环体内声明
Random rdm = new Random();
for (int i = 0; i < 10; i++)
{               
 Console.WriteLine(rdm.Next(1,10));
}

练习： 随机发扑克牌给4个人

using System;
using System.Collections;

namespace ConsoleApplication1
{
    class Class2
    {
        public static void Main(string[] args)
        {
            ArrayList list = InitialCards();
            ArrayList[] player = new ArrayList[4];
            player[0] = new ArrayList();
            player[1] = new ArrayList();
            player[2] = new ArrayList();
            player[3] = new ArrayList();

            Random rdm = new Random();
            string card = null;
            int index = 0;
            while (list.Count > 0)
            {
                index = rdm.Next(0, list.Count);
                card = list[index].ToString();
                player[(54-list.Count)%4].Add(card);
                list.RemoveAt(index);
            }

            DisplayReslut(player);
        }

        private static void DisplayReslut(ArrayList[] player)
        {
            for (int i = 0; i < player.Length; i++)
            {
                Console.WriteLine("player[{0}]", i);
                int k = 0;
                foreach (string card2 in player[i])
                {
                    if (k % 5 == 0)
                    {
                        Console.WriteLine();
                    }
                    ++k;
                    Console.Write("{0}/t", card2);

                }
                Console.WriteLine();
            }
        }

 

        public static ArrayList InitialCards()
        {
            string[] color = new string[] { "红桃", "黑桃", "方块", "梅花" };
            string[] point = new string[] { "A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K" };

            ArrayList list = new ArrayList(54);
            for (int i = 0; i < color.Length; i++)
            {
                for (int j = 0; j < point.Length; j++)
                {
                    list.Add(color[i] + "" + point[j]);
                }
            }
            list.Add("大王");
            list.Add("小王");

            return list;
        }

    }
}