Method Repeat

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Repeat<TResult>(TResult)

Generates a sequence by repeating the given value infinitely.

Declaration
public static IEnumerable<TResult> Repeat<TResult>(TResult value)
Parameters
Type Name Description
TResult value

Value to repeat in the resulting sequence.
Returns
Type Description
IEnumerable<TResult>

Sequence repeating the given value infinitely.
Type Parameters
Name Description
TResult

Result sequence element type.
Examples

The following code example demonstrates how to repeat a value using Repeat.

// Repeat a value indefinitely
var result = SuperEnumerable
    .Repeat(1)
    .Take(10);

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

// This code produces the following output:
// [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
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Repeat<TSource>(IEnumerable<TSource>)

Repeats and concatenates the source sequence infinitely.

Declaration
public static IEnumerable<TSource> Repeat<TSource>(this IEnumerable<TSource> source)
Parameters
Type Name Description
IEnumerable<TSource> source

Source sequence.
Returns
Type Description
IEnumerable<TSource>

Sequence obtained by concatenating the source sequence to itself infinitely.
Type Parameters
Name Description
TSource

Source sequence element type.
Remarks

This operator uses deferred execution and streams its result. The source sequence is cached as the returned IEnumerable<T> is enumerated. When source has completed, the values from source will be returned again indefinitely.

The cache is maintained separately for each IEnumerator<T> generated from the returned IEnumerable<T>.

Examples

The following code example demonstrates how to repeat a value using Repeat.

var sequence = Enumerable.Range(1, 3);

// Repeat a sequence indefinitely
var result = sequence
    .Repeat()
    .Take(10);

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

// This code produces the following output:
// [1, 2, 3, 1, 2, 3, 1, 2, 3, 1]
Exceptions
Type Condition
ArgumentNullException

source is null.
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Repeat<TSource>(IEnumerable<TSource>, int)

Repeats and concatenates the source sequence the given number of times.

Declaration
public static IEnumerable<TSource> Repeat<TSource>(this IEnumerable<TSource> source, int count)
Parameters
Type Name Description
IEnumerable<TSource> source

Source sequence.
int count

Number of times to repeat the source sequence.
Returns
Type Description
IEnumerable<TSource>

Sequence obtained by concatenating the source sequence to itself the specified number of times.
Type Parameters
Name Description
TSource

Source sequence element type.
Remarks

This operator uses deferred execution and streams its result. The source sequence is cached as the returned IEnumerable<T> is enumerated. When source has completed, the values from source will be returned again count times.

The cache is maintained separately for each IEnumerator<T> generated from the returned IEnumerable<T>.

Examples

The following code example demonstrates how to repeat a value using Repeat.

var sequence = Enumerable.Range(1, 3);

// Repeat a sequence
var result = sequence
    .Repeat(3);

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

// This code produces the following output:
// [1, 2, 3, 1, 2, 3, 1, 2, 3]
Exceptions
Type Condition
ArgumentNullException

source is null.
ArgumentOutOfRangeException

count is less than or equal to 0.