C# - Array.Sort: Keys, Values and Ranges

Array.Sort. This method orders elements in an array. It modifies the array in-place. It handles different types of elements, including strings and ints.

Key feature. Array.Sort has some important features. We can sort 2 arrays at once: one is used as the keys array, and a second is used as the values array.

Sort

Array

Keys and values. In this example here we sort 2 arrays by a key array. First we declare the arrays (keys and values) and set the elements in them.

Next We call the Array.Sort overload that accepts two arrays. The first argument is the keys array and the second is the values array.

Finally The program prints out the keys array in its sorted order, and the values array in its sorted order.

Console.WriteLine

using System; // Sort keys and values. int[] keys = { 4, 7, 2, 0 }; int[] values = { 1, 2, 3, 4 }; Array.Sort(keys, values); foreach (int key in keys) { Console.Write(key); Console.Write(' '); } Console.WriteLine(); foreach (int value in values) { Console.Write(value); Console.Write(' '); } Console.WriteLine();

0 2 4 7 4 3 1 2

Simple example. This program allocates an array of 4 integers. Next it calls the Array.Sort method. This sorts the elements in-place—we do not need to assign a variable.

int Array

Detail We enumerate the integers in the sorted array, printing them to the console.

using System; // Simple sort call. int[] values = { 4, 7, 2, 0 }; Array.Sort(values); foreach (int value in values) { Console.Write(value); Console.Write(' '); } Console.WriteLine();

0 2 4 7

Array reference. This program creates an array. Then it references the newly-created int array as an Array. We can do this because the int[] type is derived from the Array type.

Next This Array reference is passed to the Array.Sort method, which can sort the elements.

And Before program completion, we display the sorted elements in the Array reference.

using System; // Sort Array reference. int[] values = { 4, 7, 2, 0 }; Array array = values; Array.Sort(array); foreach (int value in array) { Console.Write(value); Console.Write(' '); } Console.WriteLine();

0 2 4 7

Range example. This program creates an integer array upon the managed heap. Then, it calls the Array.Sort method with three arguments.

Info The arguments are the array reference (int[]), the starting index (0) and the number of elements to sort past that index.

Note This program uses 0, 3 to sort only the first three elements. It sorts a range of elements.

Tip You can see in the results that the first three elements are sorted in ascending numeric order.

And The fourth element 0 is still at the end because it was not included in the sorting operation.

using System; // Sort range of elements. int[] values = { 4, 7, 2, 0 }; Array.Sort(values, 0, 3); foreach (int value in values) { Console.Write(value); Console.Write(' '); } Console.WriteLine();

2 4 7 0

Summary. Array.Sort has many overloads. We can modify the arguments to invoke the more sophisticated versions of the method. The List's Sort() method internally calls Array.Sort.

Sort List, Lambda