Method PadStart

PadStart<TSource>(IEnumerable<TSource>, int)

Pads a sequence with default values in the beginning if it is narrower (shorter in length) than a given width.

Declaration

public static IEnumerable<TSource?> PadStart<TSource>(this IEnumerable<TSource> source, int width)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The sequence to pad.
int	width	The width/length below which to pad.

Returns

Type	Description
IEnumerable<TSource>	Returns a sequence that is at least as wide/long as the width/length specified by the width parameter.

Type Parameters

Name	Description
TSource	The type of the elements of source.

Remarks

This operator uses deferred execution and streams its results.

Examples

The following code example demonstrates how to pad a sequence using PadStart.

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

// Pad a sequence until it is at least a certain length
var result = sequence
    .PadStart(6);

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

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

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentOutOfRangeException	width is less than 0.

PadStart<TSource>(IEnumerable<TSource>, int, TSource)

Pads a sequence with default values in the beginning if it is narrower (shorter in length) than a given width.

Declaration

public static IEnumerable<TSource> PadStart<TSource>(this IEnumerable<TSource> source, int width, TSource padding)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The sequence to pad.
int	width	The width/length below which to pad.
TSource	padding	The value to use for padding.

Returns

Type	Description
IEnumerable<TSource>	Returns a sequence that is at least as wide/long as the width/length specified by the width parameter.

Type Parameters

Name	Description
TSource	The type of the elements of source.

Remarks

This operator uses deferred execution and streams its results.

Examples

The following code example demonstrates how to pad a sequence using PadStart.

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

// Pad a sequence until it is at least a certain length
var result = sequence
    .PadStart(6, -5);

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

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

Exceptions

Type	Condition
ArgumentNullException	source is null.
ArgumentOutOfRangeException	width is less than 0.

PadStart<TSource>(IEnumerable<TSource>, int, Func<int, TSource>)

Pads a sequence with default values in the beginning if it is narrower (shorter in length) than a given width.

Declaration

public static IEnumerable<TSource> PadStart<TSource>(this IEnumerable<TSource> source, int width, Func<int, TSource> paddingSelector)

Parameters

Type	Name	Description
IEnumerable<TSource>	source	The sequence to pad.
int	width	The width/length below which to pad.
Func<int, TSource>	paddingSelector	A function to generate the value used as padding.

Returns

Type	Description
IEnumerable<TSource>	Returns a sequence that is at least as wide/long as the width/length specified by the width parameter.

Type Parameters

Name	Description
TSource	The type of the elements of source.

Remarks

This operator uses deferred execution and streams its results.

Examples

The following code example demonstrates how to pad a sequence using PadStart.

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

// Pad a sequence until it is at least a certain length
var result = sequence
    .PadStart(6, i => -i);

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

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

Exceptions

Type	Condition
ArgumentNullException	source or paddingSelector is null.
ArgumentOutOfRangeException	width is less than 0.