Method Backsert

Backsert<T>(IEnumerable<T>, IEnumerable<T>, int)

Inserts the elements of a sequence into another sequence at a specified index from the tail of the sequence, where zero always represents the last position, one represents the second-last element, two represents the third-last element and so on.

Declaration

[Obsolete("Backsert has been replaced by Insert(second, Index index)")]
public static IEnumerable<T> Backsert<T>(this IEnumerable<T> first, IEnumerable<T> second, int index)

Parameters

Type	Name	Description
IEnumerable<T>	first	The source sequence.
IEnumerable<T>	second	The sequence that will be inserted.
int	index	The zero-based index from the end of first where elements from second should be inserted. second.

Returns

Type	Description
IEnumerable<T>	A sequence that contains the elements of first plus the elements of second inserted at the given index from the end of first.

Type Parameters

Name	Description
T	Type of elements in all sequences.

Remarks

This operator uses deferred execution and streams its results.

Examples

Note

Backsert has been deprecated in favor of Insert. Please see here for documentation on the equivalent method.

The following code example demonstrates how to insert one sequence into another, using Backsert.

var first = Enumerable.Range(1, 5);
var second = Enumerable.Range(1, 5);
            
// Insert one sequence into another
var result = first
    .Backsert(second, 2);
            
Console.WriteLine(string.Join(", ", result));

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

Exceptions

Type	Condition
ArgumentNullException	first or second is null.
ArgumentOutOfRangeException	index is negative.
ArgumentOutOfRangeException	Thrown lazily if index is greater than the length of first.