using System;using System.Collections.Generic;using System.Diagnostics;using System.Linq;using System.Text;using System.Threading; namespace ConsoleApp1{  class Program  {    /// <summary>    /// 字符串，數組和List的截取，轉換    /// </summary>    /// <param name="args"></param>    static void Main(string[] args)    {      string str = "abcdefghij1234567890";      int i = 4;      string str1 = str.Substring(0, i);//截取字符串前i位--abcd      string str2 = str.Remove(i, str.Length - i);//移除字符串i位后面的字符=截取字符串前i位--abcd      string str3 = str.Remove(0, i);//截取字符串i位之后的字符串--efghij1234567890      string str4 = str.Substring(i);//截取字符串i位之后的字符串--efghij1234567890      string str5 = str.Substring(str.Length - i);//截取字符串后i位--7890      string str6 = str.Remove(0, str.Length - i);//截取字符串后i位--7890      string str7 = str.Substring(0, str.Length - i);//去掉字符串后i位--abcdefghij123456      string str8 = str.Remove(str.Length - i, i);//去掉字符串后i位--abcdefghij123456      string str9 = str.Replace("abc", "ABC");//替換字符串中的字符串--ABCdefghij1234567890      string str0 = str.ToUpper();//小寫字母轉換成大寫字母--ABCDEFGHIJ1234567890      string str10 = str0.ToLower();//大寫字母轉換成小寫字母--abcdefghij1234567890      string str11= str.Substring(str.Length - 1, 1);//截取字符串最后一位--0      int m = str.IndexOf("cde") + 1;      int n = str.IndexOf("23");      string str12 = str.Substring(m, n - m + 2);//截取從開始字符串到結束字符串范圍--cdefghij123      string s = "a,b,c,d,e,f,g,h,i,j";      string[] strArray = s.Split(','); //字符串轉數組      string str13 = string.Join(",", strArray);//數組轉字符串      List<string> list = new List<string>(s.Split(','));//字符串轉List      string str14 = string.Join(",", list.ToArray());//List轉字符串      string[] str15 = list.ToArray();//List轉數組      List<string> listS = new List<string>(str15);//數組轉List      Console.WriteLine(str0);      Console.WriteLine(str12);      Console.ReadLine();    }  }   }