Method PadStart

View Source

PadStart<TSource>(IAsyncEnumerable<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 IAsyncEnumerable<TSource?> PadStart<TSource>(this IAsyncEnumerable<TSource> source, int width)
Parameters
Type Name Description
IAsyncEnumerable<TSource> source

The sequence to pad.
int width

The width/length below which to pad.
Returns
Type Description
IAsyncEnumerable<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
int[] numbers = { 123, 456, 789 };
var result = numbers.PadStart(5);
    The <code>result</code> variable will contain <code>{ 0, 0, 123, 456, 789 }</code>.
Exceptions
Type Condition
ArgumentNullException

source is null.
ArgumentOutOfRangeException

width is less than 0.
View Source

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

Pads a sequence with a given filler value in the beginning if it is narrower (shorter in length) than a given width. An additional parameter specifies the value to use for padding.

Declaration
public static IAsyncEnumerable<TSource> PadStart<TSource>(this IAsyncEnumerable<TSource> source, int width, TSource padding)
Parameters
Type Name Description
IAsyncEnumerable<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
IAsyncEnumerable<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
int[] numbers = { 123, 456, 789 };
var result = numbers.PadStart(5, -1);
    The <code>result</code> variable will contain <code>{ -1, -1, 123, 456, 789 }</code>.
Exceptions
Type Condition
ArgumentNullException

source is null.
ArgumentOutOfRangeException

width is less than 0.
View Source

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

Pads a sequence with a dynamic filler value in the beginning if it is narrower (shorter in length) than a given width. An additional parameter specifies the function to calculate padding.

Declaration
public static IAsyncEnumerable<TSource> PadStart<TSource>(this IAsyncEnumerable<TSource> source, int width, Func<int, TSource> paddingSelector)
Parameters
Type Name Description
IAsyncEnumerable<TSource> source

The sequence to pad.
int width

The width/length below which to pad.
Func<int, TSource> paddingSelector

Function to calculate padding given the index of the missing element.
Returns
Type Description
IAsyncEnumerable<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
int[] numbers = { 123, 456, 789 };
var result = numbers.PadStart(6, i => -i);
    The <code>result</code> variable will contain <code>{ 0, -1, -2, 123, 456, 789 }</code>.
Exceptions
Type Condition
ArgumentNullException

source is null.
ArgumentNullException

paddingSelector is null.
ArgumentOutOfRangeException

width is less than 0.