1 Replace

string sayHello = "Hello World!";
Console.WriteLine(sayHello);
sayHello = sayHello.Replace("Hello", "張濤");
Console.WriteLine(sayHello);

Hello World!
張濤 World!

2.ToLower() 全部小寫

ToUpper()全部大寫

3.Contains

string songLyrics = "You say goodbye, and I say hello
 
";
Console.WriteLine(songLyrics.Contains("goodbye"));
Console.WriteLine(songLyrics.Contains("greetings"));
True
False

string songLyrics = "You say goodbye, and I say hello";
Console.WriteLine(songLyrics.StartsWith("You"));
Console.WriteLine(songLyrics.StartsWith("goodbye"));

Console.WriteLine(songLyrics.EndsWith(
 
"hello"));
Console.WriteLine(songLyrics.EndsWith("goodbye"));

True
False
True
False

C#之字符串