C# String.IndexOf()用法及代码示例

C# 中的 String.IndexOf() 方法用于查找指定 Unicode 字符或字符串在此实例中第一次出现的从零开始的索引。

用法

语法如下 -

public int IndexOf (string val);

上面， val 是要查找的字符串。

示例

现在让我们看一个例子 -

using System;
public class Demo {
   public static void Main(String[] args) {
      string str1 = "Jacob";
      string str2 = "John";
      Console.WriteLine("String 1 = "+str1);
      Console.WriteLine("HashCode of String 1 = "+str1.GetHashCode());
      Console.WriteLine("Index of character 'o' is str1 = " + str1.IndexOf("o"));
      Console.WriteLine("\nString 2 = "+str2);
      Console.WriteLine("HashCode of String 2 = "+str2.GetHashCode());
      Console.WriteLine("Index of character 'o' is str2 =" + str2.IndexOf("o"));
      bool res = str1.Contains(str2);
      if (res)
         Console.WriteLine("Found!");
      else
         Console.WriteLine("Not found!");
   }
}

输出

这将产生以下输出 -

String 1 = Jacob
HashCode of String 1 = -790718923
Index of character 'o' is str1 = 3
String 2 = John
HashCode of String 2 = -1505962600
Index of character 'o' is str2 =1
Not found!

示例

现在让我们看另一个例子 -

using System;
public class Demo {
   public static void Main(String[] args) {
      string str1 = "Kevin";
      string str2 = "Evin";
      Console.WriteLine("String 1 = "+str1);
      Console.WriteLine("HashCode of String 1 = "+str1.GetHashCode());
      Console.WriteLine("Index of character 'k' in str1 = " + str1.IndexOf("k"));
      Console.WriteLine("\nString 2 = "+str2);
      Console.WriteLine("HashCode of String 2 = "+str2.GetHashCode());
      Console.WriteLine("Index of character 'k' in str2 =" + str2.IndexOf("k"));
      bool res = str1.Contains(str2);
      if (res)
         Console.WriteLine("Found!");
      else
         Console.WriteLine("Not found!");
   }
}

输出

这将产生以下输出 -

String 1 = Kevin
HashCode of String 1 = -768104063
Index of character 'k' in str1 = -1
String 2 = Evin
HashCode of String 2 = 1223510568
Index of character 'k' in str2 =-1
Not found!