Method CopyTo

CopyTo<TSource>(IEnumerable<TSource>, Span<TSource>)

Copies the contents of a sequence into a provided span.

Declaration

public static int CopyTo<TSource>(this IEnumerable<TSource> source, Span<TSource> span)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The source sequence.
Span<TSource>	span	The span that is the destination of the elements copied from source.

Returns

Type	Description
int	The number of elements actually copied.

Type Parameters

Name	Description
TSource	The type of elements of source

Remarks

All data from source will be copied to span if possible.

If source is shorter than span, then any remaining elements will be untouched. If source is longer than span, then an exception will be thrown.

This operator executes immediately.

Examples

The following code example demonstrates how to copy data to a span using the CopyTo operator.

var sequence = Enumerable.Range(1, 5);
var destination = new int[7];
var span = destination.AsSpan();
            
// Copy the provided sequence to a span
var result = sequence.CopyTo(span[1..]);

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

// This code produces the following output:
// 5
// [0, 1, 2, 3, 4, 5, 0]

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentException	span is not long enough to hold the data from sequence.

CopyTo<TSource>(IEnumerable<TSource>, TSource[])

Copies the contents of a sequence into a provided span.

Declaration

public static int CopyTo<TSource>(this IEnumerable<TSource> source, TSource[] array)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The source sequence.
TSource[]	array	The span that is the destination of the elements copied from source.

Returns

Type	Description
int	The number of elements actually copied.

Type Parameters

Name	Description
TSource	The type of elements of source

Remarks

All data from source will be copied to array if possible.

If source is shorter than array, then any remaining elements will be untouched. If source is longer than array, then an exception will be thrown.

This operator executes immediately.

Examples

The following code example demonstrates how to copy data to an array using the CopyTo operator.

var sequence = Enumerable.Range(1, 5);
var destination = new int[5];
            
// Copy the provided sequence to an array
var result = sequence.CopyTo(destination);

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

// This code produces the following output:
// 5
// [1, 2, 3, 4, 5]

Exceptions

Type	Condition
ArgumentNullException	source or array is null.
ArgumentException	array is not long enough to hold the data from sequence.

CopyTo<TSource>(IEnumerable<TSource>, IList<TSource>)

Copies the contents of a sequence into a provided list.

Declaration

public static int CopyTo<TSource>(this IEnumerable<TSource> source, IList<TSource> list)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The source sequence.
IList<TSource>	list	The list that is the destination of the elements copied from source.

Returns

Type	Description
int	The number of elements actually copied.

Type Parameters

Name	Description
TSource	The type of elements of source

Remarks

All data from source will be copied to list, starting at position 0.

If source is shorter than list, then any remaining elements will be untouched. If source is longer than list, then an exception may be thrown if the list has a fixed size (an Array, for example).

This operator executes immediately.

Examples

The following code example demonstrates how to copy data to a list using the CopyTo operator.

var sequence = Enumerable.Range(1, 5);
var destination = new List<int>() { -1, -2, };
            
// Copy the provided sequence to a list
var result = sequence.CopyTo(destination);

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

// This code produces the following output:
// 5
// [1, 2, 3, 4, 5]

Exceptions

Type	Condition
ArgumentNullException	source or list is null.
NotSupportedException	The list is readonly, or does not allow increasing the size via Add(T)

CopyTo<TSource>(IEnumerable<TSource>, IList<TSource>, int)

Copies the contents of a sequence into a provided list.

Declaration

public static int CopyTo<TSource>(this IEnumerable<TSource> source, IList<TSource> list, int index)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The source sequence.
IList<TSource>	list	The list that is the destination of the elements copied from source.
int	index	The position in list at which to start copying data.

Returns

Type	Description
int	The number of elements actually copied.

Type Parameters

Name	Description
TSource	The type of elements of source

Remarks

All data from source will be copied to list, starting at position index.

If source is shorter than list, then any remaining elements will be untouched. If source is longer than list, then an exception may be thrown if the list has a fixed size (an Array, for example).

This operator executes immediately.

Examples

The following code example demonstrates how to copy data to a list using the CopyTo operator.

var sequence = Enumerable.Range(1, 5);
var destination = new List<int>() { -1, -2, };
            
// Copy the provided sequence to a list at a specified index
var result = sequence.CopyTo(destination, 2);

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

// This code produces the following output:
// 5
// [-1, -2, 1, 2, 3, 4, 5]

Exceptions

Type	Condition
ArgumentNullException	source or list is null.
ArgumentOutOfRangeException	index is less than 0.
NotSupportedException	The list is readonly, or does not allow increasing the size via Add(T)