C# String Join()

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {
   
      // creates a string array.
      string[] text = { "C#", "Java", "C++" };
        
      // joins string with space between them
      Console.WriteLine(String.Join(" ", text));

      Console.ReadLine();    
    }
  } 
}

// Output: C# Java C++

Join() Syntax

The syntax of the string Join() method is:

String.Join(String separator, String[] value, Int32 startIndex, Int32 count)

Here, Join() is a method of class String.

Join() Parameters

The Join() method takes the following parameters:

• separator - the separator to join the elements
• value - an array of strings to join
• startIndex - the first item in value to join
• count - number of elements to join (starts from startIndex)

Join() Return Value

• returns a string that consists of the elements separated by the separator

Example 1: C# String Join()

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {
   
      // creates a string array.
      string[] text = {"C#", "Java", "C++"};
        
      // joins string with "/" between them
      string result = String.Join("/", text);
      Console.WriteLine(result);

      Console.ReadLine();    
    }
  } 
}

Output

C#/Java/C++

Here, the text elements "C#", "Java", and "C++" to the Join() are joined using the / separator.

Example 2: Join() With Start Index and Count

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {
   
      // Creating a string array
      string[] text = {"C#", "Java", "C++", "Swift", "Go"};

      // joins 2 strings from index 1
      string s1 = String.Join("-", text, 1, 2);

      Console.WriteLine(s1);

      Console.ReadLine();    
    }
  } 
}

Output

Java-C++

In the above example, notice the line,

string s1 = String.Join("-", text, 1, 2);

Here,

• 1 - starting index of text to join (index of "Java")
• 2 - number of elements to join