AsyncEnumerable.CountBy 方法

定義

命名空間:: System.Linq

組件:: System.Linq.AsyncEnumerable.dll

套件:: System.Linq.AsyncEnumerable v11.0.0

重要

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多載

名稱	Description
CountBy<TSource,TKey>(IAsyncEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	回傳來源序列中依鍵分組的元素數量。
CountBy<TSource,TKey>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<TKey>>, IEqualityComparer<TKey>)	回傳來源序列中依鍵分組的元素數量。

CountBy<TSource,TKey>(IAsyncEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

來源:: CountBy.cs

來源:: CountBy.cs

來源:: CountBy.cs

回傳來源序列中依鍵分組的元素數量。

public static System.Collections.Generic.IAsyncEnumerable<System.Collections.Generic.KeyValuePair<TKey,int>> CountBy<TSource,TKey>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey>? keyComparer = default);

static member CountBy : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, 'Key> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.IAsyncEnumerable<System.Collections.Generic.KeyValuePair<'Key, int>>

<Extension()>
Public Function CountBy(Of TSource, TKey) (source As IAsyncEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), Optional keyComparer As IEqualityComparer(Of TKey) = Nothing) As IAsyncEnumerable(Of KeyValuePair(Of TKey, Integer))

類型參數

TSource

元素 source的類型。

TKey

由返回 keySelector的金鑰類型。

參數

source: IAsyncEnumerable<TSource>

包含待計數元素的序列。

keySelector: Func<TSource,TKey>

一個用來提取每個元素鍵值的函式。

keyComparer: IEqualityComparer<TKey>

一個 IEqualityComparer<T> 比較鑰匙的對象。

傳回

IAsyncEnumerable<KeyValuePair<TKey,Int32>>

一個包含每個鍵出現頻率的 source可枚舉。

例外狀況

ArgumentNullException

keySelector 是 null。

適用於

CountBy<TSource,TKey>(IAsyncEnumerable<TSource>, Func<TSource,CancellationToken,ValueTask<TKey>>, IEqualityComparer<TKey>)

來源:: CountBy.cs

來源:: CountBy.cs

來源:: CountBy.cs

回傳來源序列中依鍵分組的元素數量。

public static System.Collections.Generic.IAsyncEnumerable<System.Collections.Generic.KeyValuePair<TKey,int>> CountBy<TSource,TKey>(this System.Collections.Generic.IAsyncEnumerable<TSource> source, Func<TSource,System.Threading.CancellationToken,System.Threading.Tasks.ValueTask<TKey>> keySelector, System.Collections.Generic.IEqualityComparer<TKey>? keyComparer = default);

static member CountBy : System.Collections.Generic.IAsyncEnumerable<'Source> * Func<'Source, System.Threading.CancellationToken, System.Threading.Tasks.ValueTask<'Key>> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.IAsyncEnumerable<System.Collections.Generic.KeyValuePair<'Key, int>>

<Extension()>
Public Function CountBy(Of TSource, TKey) (source As IAsyncEnumerable(Of TSource), keySelector As Func(Of TSource, CancellationToken, ValueTask(Of TKey)), Optional keyComparer As IEqualityComparer(Of TKey) = Nothing) As IAsyncEnumerable(Of KeyValuePair(Of TKey, Integer))