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How to efficiently fill array with given value?

C#  |  .NET

If you want to efficiently fill the whole array with a given value (5 in the example), you can use the following code:

int[] array = new int[100];
Array.Fill(array, 5);

Filling only a part of an array is supported as well, as you can see below:

int[] array = new int[10];
Array.Fill(array, 5, 2, 4);

The following parameters of the Fill static method indicate:

  • the array (array),
  • a value to fill (5),
  • an index where the fill starts (2),
  • the number of elements to fill (4).

So, the code above fills 4 elements, starting from index 2. Then, the array contains the elements: [0, 0, 5, 5, 5, 5, 0, 0, 0, 0].

If you want to learn much more about arrays, as well as about other data structures, I encourage you to take a look at my book, namely the Second Edition of C# Data Structures and Algorithms, published by Packt Publishing in 2024. You can buy it here.

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Hello, I am Marcin

Reliable entrepreneur with 10+ years of companies operation, such as CEO at a few IT companies. I was an author of a few software & hardware products, still open to new ideas & cooperation.

Helpful expert with 10+ years of experience, together with PhD and DSc in Computer Science. I was an author of books and publications, as well as an expert in international projects.

Experienced developer with 10+ years of development and 100+ completed projects. I worked on various complex international projects, e.g. at Microsoft in USA and as CTO at a few companies. I have MCP, MCTS and MCPD certificates.

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I am an author of a few books and numerous publications, also in high-quality international scientific journals.

If you want to learn data structures and algorithms in the context of C#, let's take a look at my newest book. It is the second edition of C# Data Structures and Algorithms. You can buy it here.


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