C# 字符串、数组和List的截取和转换

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，数组和List的截取，转换
        /// </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");//替换字符串中的字符串--ABCdefghij1234567890
            string str0 = str.ToUpper();//小写字母转换成大写字母--ABCDEFGHIJ1234567890
            string str10 = str0.ToLower();//大写字母转换成小写字母--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);//截取从开始字符串到结束字符串范围--cdefghij123
            string s = "a,b,c,d,e,f,g,h,i,j";
            string[] strArray = s.Split(','); //字符串转数组
            string str13 = string.Join(",", strArray);//数组转字符串
            List<string> list = new List<string>(s.Split(','));//字符串转List
            string str14 = string.Join(",", list.ToArray());//List转字符串
            string[] str15 = list.ToArray();//List转数组
            List<string> listS = new List<string>(str15);//数组转List
            var intersectedList = list.Intersect(listS);//两个List交集
            var expectedList = list.Except(listS);//两个List取差
            var mergedList = list.Merge(listS);//两个List取联集
            var result = list.Union(listS).ToList<int>(); //除去重复 
            var result1 = list.Concat(listS).ToList<int>();//保留重复
            var result2 = list.BinarySearch("1");//判断集合中是否包含某个值.如果包含则返回0
            Console.WriteLine(str0);
            Console.WriteLine(str12);
            Console.ReadLine();
        }
    }
     
}