Array Class & Utility Methods

Syntax

Array.MethodName(array);

Examples

int[] numbers = { 5, 2, 8, 1, 9 };

Array.Sort(numbers);
Console.WriteLine(string.Join(", ", numbers));  // 1, 2, 5, 8, 9

Array.Reverse(numbers);
Console.WriteLine(string.Join(", ", numbers));  // 9, 8, 5, 2, 1

int[] sorted = { 1, 3, 5, 7, 9 };
int index = Array.BinarySearch(sorted, 7);
Console.WriteLine(index);  // 3

int missing = Array.BinarySearch(sorted, 4);
Console.WriteLine(missing);  // negative - not found

int[] numbers = { 1, 2, 3 };
Array.Resize(ref numbers, 5);

Console.WriteLine(numbers.Length);  // 5
Console.WriteLine(string.Join(", ", numbers));  // 1, 2, 3, 0, 0

int[] original = { 1, 2, 3, 4, 5 };

int[] fullCopy = (int[])original.Clone();

int[] partial = new int[3];
Array.Copy(original, 1, partial, 0, 3);  // copy 3 elements starting at index 1
Console.WriteLine(string.Join(", ", partial));  // 2, 3, 4

Best practices

• Use string.Join() to print array contents readably - printing an array directly with WriteLine() shows its type name, not its contents
• Always sort with Array.Sort() before calling Array.BinarySearch() - binary search requires the array to already be sorted to work correctly
• Remember Array.Resize() actually creates a brand new array under the hood and copies the data - it is not a cheap operation for large arrays used repeatedly
• Use a List<T> instead of repeatedly resizing an array when the size genuinely needs to change often

At a glance

Purpose

Applications on the .NET platform

File extension

.cs

Runs in

.NET runtime

Usually used with

.NET SDK and libraries

Specifications & further reading

• C# language reference

Related C# documentation