LINQ Sequence Generation

Enumerable.Range(start, count)

A LINQ sequence-generation method that creates a sequence of consecutive integers beginning at a specified value and containing a specified number of elements. Domain: C# → .NET → System.Linq → Sequence Generation & Combination

IEnumerable numbers = Enumerable.Range(1, 5);

Generates the sequence 1, 2, 3, 4, 5.

var numbers = Enumerable.Range(10, 4);

Generates four consecutive integers beginning at 10: 10, 11, 12, 13.

Enumerable.Repeat(element, count)

A LINQ sequence-generation method that creates a sequence containing the same specified element repeated a specified number of times.

IEnumerable values = Enumerable.Repeat("Hello", 3);

Generates a sequence containing "Hello" three times.

var zeros = Enumerable.Repeat(0, 5);

Generates a sequence containing five zero values.

Enumerable.Empty()

A LINQ sequence-generation method that returns an empty IEnumerable of the specified element type.

IEnumerable numbers = Enumerable.Empty();

Creates an empty sequence whose element type is int.

IEnumerable names = Enumerable.Empty();

Creates an empty sequence whose element type is string.

Concat()

A LINQ sequence-combination operator that places the elements of one sequence after the elements of another sequence while preserving duplicates.

var results = first.Concat(second);

Returns a sequence containing all elements from first followed by all elements from second.

Concat() vs Union()

Concat() combines sequences while preserving duplicate elements, whereas Union() combines sequences using set semantics and removes duplicates according to equality.

Append()

A LINQ sequence-combination operator that returns a sequence with one specified element added after all elements of the source sequence.

var results = numbers.Append(100);

Returns the original sequence followed by the value 100.

Prepend()

A LINQ sequence-combination operator that returns a sequence with one specified element placed before all elements of the source sequence.

var results = numbers.Prepend(0);

Returns a sequence beginning with 0 followed by all elements from the original sequence.

var results = numbers.Prepend(0).Append(100);

Returns a sequence with 0 placed before the original elements and 100 placed after them.

Append() and Prepend() Behavior

Append() and Prepend() return new sequence views and do not directly modify the original source collection.

Sequence Generation

The creation of an IEnumerable sequence programmatically without requiring an existing collection of source elements.

Sequence Combination

The construction of a resulting sequence by connecting existing sequences or adding elements before or after a sequence.