How to create an array with non-default repeated values in C#?

We can create an array with non-default repeated values using Enumerable.Repeat(). This method creates a sequence that contains one repeated value a specified number of times. It requires the System.Linq namespace to be included.

Syntax

Following is the syntax for using Enumerable.Repeat() −

IEnumerable<T> Enumerable.Repeat<T>(T element, int count)

Parameters

• element − The value to be repeated in the sequence.

• count − The number of times to repeat the value in the generated sequence.

Return Value

Returns an IEnumerable<T> that contains a repeated value. To convert it to an array, use the ToArray() method.

Using Enumerable.Repeat() with IEnumerable

The Enumerable.Repeat() method returns an IEnumerable sequence that can be iterated directly −

using System;
using System.Linq;

class Program {
   static void Main(string[] args) {
      var values = Enumerable.Repeat(10, 5);
      foreach (var item in values) {
         Console.WriteLine(item);
      }
   }
}

The output of the above code is −

10
10
10
10
10

Using Enumerable.Repeat() to Create an Array

To create an actual array with repeated values, call ToArray() on the result −

using System;
using System.Linq;

class Program {
   static void Main(string[] args) {
      int[] values = Enumerable.Repeat(10, 5).ToArray();
      Console.WriteLine("Array length: " + values.Length);
      foreach (var item in values) {
         Console.WriteLine(item);
      }
   }
}

The output of the above code is −

Array length: 5
10
10
10
10
10

Using Enumerable.Repeat() with Different Data Types

The method works with any data type, including strings, objects, and custom types −

using System;
using System.Linq;

class Program {
   static void Main(string[] args) {
      // String array with repeated values
      string[] names = Enumerable.Repeat("Hello", 3).ToArray();
      Console.WriteLine("String array:");
      foreach (string name in names) {
         Console.WriteLine(name);
      }
      
      // Boolean array with repeated values
      bool[] flags = Enumerable.Repeat(true, 4).ToArray();
      Console.WriteLine("\nBoolean array:");
      foreach (bool flag in flags) {
         Console.WriteLine(flag);
      }
      
      // Double array with repeated values
      double[] prices = Enumerable.Repeat(99.99, 2).ToArray();
      Console.WriteLine("\nDouble array:");
      foreach (double price in prices) {
         Console.WriteLine(price);
      }
   }
}

The output of the above code is −

String array:
Hello
Hello
Hello

Boolean array:
True
True
True
True

Double array:
99.99
99.99

Conclusion

The Enumerable.Repeat() method provides an efficient way to create arrays or sequences with repeated non-default values in C#. It works with any data type and can be easily converted to an array using ToArray() for scenarios requiring indexed access or array-specific operations.