How to concatenate two arrays in C#

In this tutorial, we are going to learn about how to concatenate the two arrays in C# with the help of examples.

Concatenation means the joining of two or more arrays into a single array.

Consider, we have the following two arrays:

int[] array1 = { 1, 2, 3 };
int[] array2 = { 4, 5, 6 };

Now, we need to join above two arrays like this:

[1, 2, 3, 4, 5, 6]

Using Enumerable.Concat() method

To concatenate the two arrays into a single array, we can use the Enumerable.Concat() method in C#.

Note: The Enumberable.Concat() is available in System.Linq namespace.

Here is an example:

using System;
using System.Linq;

class ConcatenateArrays {
  static void Main() {
   int[] array1 = { 1, 2, 3 };
   int[] array2 = { 4, 5, 6 };
   int[] result = array1.Concat(array2).ToArray();

   Console.WriteLine(String.Join(",", result));
  }
}

Output:

[1, 2, 3, 4, 5, 6]

Using AddRange() method

Similarly, we can use the AddRange() method in C# to join two arrays into a single array.

Example:

using System;
using System.Collections.Generic;

class ConcatenateArrays {
  static void Main() {
      int[] arr1 = {1, 2, 3};
      int[] arr2 = {4, 5, 6};
      var myList = new List<int>();
      myList.AddRange(arr1);
      myList.AddRange(arr2);
      int[] result = myList.ToArray();

   Console.WriteLine(String.Join(",", result));
  }
}

In the above code, we have first initialized an empty integer List and then added arr1 and arr2 to the List using the AddRange() method, at the end we have converted a list to an array using ToArray() method.