Method Shuffle

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Shuffle<T>(IEnumerable<T>)

Returns a sequence of elements in random order from the original sequence.

Declaration
public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source)
Parameters
Type Name Description
IEnumerable<T> source

The sequence from which to return random elements.
Returns
Type Description
IEnumerable<T>

A sequence of elements source randomized in their order.
Type Parameters
Name Description
T

The type of source sequence elements.
Remarks

This method is implemented by using deferred execution. However, source will be consumed in it's entirety immediately when first element of the returned sequence is consumed.

Examples

The following code example demonstrates how to shuffle a sequence using Shuffle.

var sequence = Enumerable.Range(1, 10);

// Shuffle a sequence
var result = sequence.Shuffle();

Console.WriteLine(
    "[" +
    string.Join(", ", result) +
    "]");

// One possible random output is as follows:
// [10, 9, 3, 8, 1, 6, 2, 4, 7, 5]
Exceptions
Type Condition
ArgumentNullException

source is null
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Shuffle<T>(IEnumerable<T>, Random)

Returns a sequence of elements in random order from the original sequence. An additional parameter specifies a random generator to be used for the random selection algorithm.

Declaration
public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source, Random rand)
Parameters
Type Name Description
IEnumerable<T> source

The sequence from which to return random elements.
Random rand

A random generator used as part of the selection algorithm.
Returns
Type Description
IEnumerable<T>

A sequence of elements source randomized in their order.
Type Parameters
Name Description
T

The type of source sequence elements.
Remarks

This method is implemented by using deferred execution. However, source will be consumed in it's entirety immediately when first element of the returned sequence is consumed.

Examples

The following code example demonstrates how to shuffle a sequence using Shuffle.

var sequence = Enumerable.Range(1, 10);

// Shuffle a sequence
var result = sequence.Shuffle(new Random(10));

Console.WriteLine(
    "[" +
    string.Join(", ", result) +
    "]");

// This code produces the following output:
// [1, 4, 2, 6, 3, 9, 5, 7, 10, 8]
Exceptions
Type Condition
ArgumentNullException

source or rand is null