字符串操作——课堂笔记

1.将字符串的某个字符赋值给char变量

    eg:string myString="A string";

     char myChar=myString[1];

2.将字符串的字符赋给char数组

     eg:string myString="A String";

     char [] myChars=myString.ToCharArray();

3.用foreach逐个输出string的char字符

4.可以像数组一样，用myString.Length获取元素的个数

5.将字符串中的字符改变大 写

     1).大写变小写：myString.ToLower()

     2).小写变大写：myString.ToUpper();

6.删除字符串中的空格：myString.Trim();

7.删除字符串中的其他字符

     第一步：在char数组中存储要删除的字符

     第二步：使用.Trim()命令

     eg:char [] trimChar={' ',',','e','s'};

            string  afterChangeString=myString.Trim(trimChar);

8.删除字符串前面或后面的字符

     1).前面：myString.TrimStart();

     2).后面：myString.TrimEnd();

9.在字符串的左面或后面添加空格使字符串达到指定的长度

     1).左面：myString.PadLeft(number);

     2).右面：myString.PadRight(number);

10.用指定的分隔符分隔字符串

     eg:char [] separator={' '};

            string [] mywords;

            mywords=myString.Split(separator);

失误案例：

            string myString = " My First String ";

            string deleteBlockString = myString.Trim();                            //删除字符串的空格
            char[] deleteCharArray={' ','i'};
            string deleteDirectlyCharString = myString.Trim(deleteCharArray);      //删除字符串中的空格和字符i
            string deleteStartBlockString = myString.TrimStart();                  //删除字符串开头的空格
            string deleteEndBlockString = myString.TrimEnd();                      //删除字符串结尾的空格
            Console.WriteLine("The string after delete Block is \"{0}\"", deleteBlockString);
            Console.WriteLine("The string after delete directly is \"{0}\"", deleteDirectlyCharString);
            Console.WriteLine("The string after delete start block is \"{0}\"", deleteStartBlockString);
            Console.WriteLine("The string after delete end block is \"{0}\"", deleteEndBlockString);
            Console.WriteLine("The string after delte Block is \"{0}\".\nThe string after delete directly Charracters is \"{1}\".\n",myString.Trim(),myString.Trim(deleteCharArray));
            Console.ReadKey();