案例1：LastIndexOf
class Program
{
static void Main(string[] args)
{
//LastIndexOf
string str = "Welcome!";
int index = str.LastIndexOf('o');
Console.WriteLine("'o'在字符串{0}里的索引为:{1}", str, index);
index = str.LastIndexOf('t');
if (index == -1)
{
index = str.LastIndexOf('o');
Console.Write("'t'在字符串{0}不存在", str);
}
else
{
Console.Write("'t'在字符串{0}的索引为:{1}", str,index);
}
Console.ReadKey();
}
}
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案例2：SubString 截取
class Program
{
static void Main(string[] args)
{
string str = "Welcome to NIIT!!!";
//SubString方法用于对字符串进行截取操作，返回一个截取后的子串
string substr = str.Substring(11);
Console.WriteLine("str:" + str);
Console.WriteLine("substr:" + substr);
//还可以为SubString制定截取的字符的个数
substr = str.Substring(11, 4);
Console.WriteLine("substr:" + substr);
Console.ReadKey();
}
}
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案例3：转化大小写 Tolower（）
string str = "WELCOOM TO NITT";
//ToLower()用于将字符转换为小写字母并返回转换后的字符串
string lowStr = str.ToLower();
Console.WriteLine("转换为小写"+lowStr);
//ToLower()用于将字符转换为大写字母并返回转换后的字符串
string upperStr=lowStr.ToUpper();
Console.WriteLine("转换为大写:"+upperStr);
Console.ReadKey();
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案例4 使用Trim（）效果
string str = " welcome to NIIT ";
Console.WriteLine("使用Trim()前的效果:{0}",str);
//用于除去字符串前后空白，并返回去除空白后的字符串
string trimStr = str.Trim();
Console.WriteLine("使用Trim()前的效果:{0}",trimStr);
Console.ReadKey();
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案例5 IsNullOrEmpty方法用于判断字符串是否是一个空引用(null)或者空串
//IsNullOrEmpty方法用于判断字符串是否是一个空引用(null)或者空串
string str = "";
String str1 = String.Empty;
Console.WriteLine("该字符串是否为空串:"+string.IsNullOrEmpty(str));
Console.WriteLine("该字符串是否为空串2:" + String.IsNullOrEmpty(str1));
string str2 = null;
Console.WriteLine("该字符串是否为空引用:" + String.IsNullOrEmpty(str2));
Console.ReadKey();
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案例6： 实践例子 获取邮箱用户名·
string email;
string chose;
do
{
Console.Write("请输入您的邮箱地址:");
email = Console.ReadLine();
Console.WriteLine("你输入的Email地址是:{0}", email);
int position=email.IndexOf();
Console.WriteLine(position);
if (!string.IsNullOrEmpty(email) && position != -1)
{
string username = email.Substring(0, position);
Console.WriteLine("你的用户名是:{0}", username);
}
else
{
Console.WriteLine("你输入的邮箱格式不正确！");
}
Console.Write("是否继续?(yes/no)");
chose = Console.ReadLine();
chose = chose.Trim().ToLower();
Console.WriteLine(email);
}
while (chose.Equals("yes"));
Console.ReadKey();
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案例7 ：分割字符 连接字符
Console.Write("请输入一个字符串,用空格分隔");
string str = Console.ReadLine();
//分割字符串
string[] a = str.Split(' ');
Console.WriteLine("分隔后:");
for (int i = 0; i < a.Length; i++)
{
Console.WriteLine(a[i]);
}
String joinstr = String.Join("_", a);
Console.WriteLine(joinstr);
Console.ReadKey()
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案例8：Format 制表！
Console.Write("请输入姓名:");
string name = Console.ReadLine();
Console.Write("请输入身高:");
string height = Console.ReadLine();
Console.Write("请输入血型:");
string bloodType = Console.ReadLine();
Console.Write("请输入星座:");
string planet = Console.ReadLine();
Console.Write("出生年月:");
string birthday = Console.ReadLine();
Console.Write("喜欢吃的食物:");
string favourFood = Console.ReadLine();
Console.WriteLine();
Console.WriteLine("个人信息:");
string b=string.Format("name:{0}\nheight:{1}\nbloodType:{2}\nplanet:{3}\nbirthday:{4}\nfavourFood:{5}",
name, height, bloodType, planet, birthday, favourFood);
Console.WriteLine(b);
Console.ReadKey();
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