c# (字符串)

namespace TestString
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = "udfne[fedfue|fmedhfn|AE是RG[RFH|GUTF[BFG是是154|144EFRE||dfhenf";
            string str;

//去除前后空格  
            str = s.Trim();
            Console.WriteLine(str);

//全员大小写
            str = s.ToUpper();
            Console.WriteLine(str);
            str = s.ToLower();
            Console.WriteLine(str);

//将其他对象转化为字符串
            int i = 123456;
            str = i.ToString();
            Console.WriteLine(str.GetType()); //获取数据的类型

//截取字符串
            str = s.Substring(0, 2); //开始索引位,长度
            Console.WriteLine(str);

//替换字符串
            str = s.Replace("|","--"); //被替换字符,替换字符
            Console.WriteLine(str);

//拆分字符串并返回字符串数组
            string[] ss = s.Split(‘|‘);  //根据字符拆分
            foreach (string j in ss)
            {
                Console.WriteLine(j);
            }
            ss = s.Split(new char[] { ‘|‘, ‘[‘ }, StringSplitOptions.None);  //根据多个字符拆分
            ss = s.Split(new char[] { ‘|‘, ‘[‘ }, StringSplitOptions.RemoveEmptyEntries);  //根据多个字符拆分去除返回数组的空元素(空格不是空元素)
            foreach (string j in ss)
            {
                Console.WriteLine(j);
            }
            ss = s.Split(new string[] { "是" }, StringSplitOptions.None);  //根据一个或多个字符串拆分
            ss = s.Split(new string[] { "是" }, StringSplitOptions.RemoveEmptyEntries);  //根据一个或多个字符串拆分去除返回数组的空元素(空格不是空元素)
            foreach (string j in ss)
            {
                Console.WriteLine(j);
            }

//拷贝字符串到字符串数组
            char[] c = s.ToCharArray();
            foreach (char j in c)
            {
                Console.WriteLine(j);
            }

//判断字符串中是否存在某字符并获取其字符第一次出现的位置
            bool b = s.Contains("是");
            Console.WriteLine(b);
            int ii = s.IndexOf("是");
            Console.WriteLine(ii);

//字符串的预处理类
            StringBuilder sb = new StringBuilder();
            for (int j = 0; j < 10; j++)
            {
                sb.Append(i.ToString());
            }
            sb[0] = ‘改‘;
            Console.WriteLine(sb);

            Console.ReadKey();
        }
    }
}