Enumerable.ToDictionary メソッド

定義

IEnumerable<T> から Dictionary<TKey,TValue> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T>.

オーバーロード

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

指定されたキー セレクター関数および要素セレクター関数に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

指定されたキー セレクター関数、比較子、および要素セレクター関数に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

指定されたキー セレクター関数に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

指定されたキー セレクター関数およびキーの比較子に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)

指定されたキー セレクター関数および要素セレクター関数に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.

public:
generic <typename TSource, typename TKey, typename TElement>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TElement> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, Func<TSource, TElement> ^ elementSelector);
public static System.Collections.Generic.Dictionary<TKey,TElement> ToDictionary<TSource,TKey,TElement> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, Func<TSource,TElement> elementSelector);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> * Func<'Source, 'Element> -> System.Collections.Generic.Dictionary<'Key, 'Element>
<Extension()>
Public Function ToDictionary(Of TSource, TKey, TElement) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), elementSelector As Func(Of TSource, TElement)) As Dictionary(Of TKey, TElement)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

TKey

keySelector によって返されるキーの型。The type of the key returned by keySelector.

TElement

elementSelector によって返される値の型。The type of the value returned by elementSelector.

パラメーター

source
IEnumerable<TSource>

Dictionary<TKey,TValue> の作成元の IEnumerable<T>An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

各要素からキーを抽出する関数。A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

各要素から結果の要素値を生成する変換関数。A transform function to produce a result element value from each element.

戻り値

Dictionary<TKey,TElement>

入力シーケンスから選択された TElement 型の値を格納する Dictionary<TKey,TValue>A Dictionary<TKey,TValue> that contains values of type TElement selected from the input sequence.

例外

sourcekeySelector、または elementSelector は、null です。source or keySelector or elementSelector is null.

- または --or- keySelectornull のキーを生成しています。keySelector produces a key that is null.

keySelector が 2 つの要素に対して重複するキーを生成しています。keySelector produces duplicate keys for two elements.

注釈

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) メソッドでは、既定の等値比較子 Default を使用してキーを比較します。The ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) method uses the default equality comparer Default to compare keys.

ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)

指定されたキー セレクター関数、比較子、および要素セレクター関数に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.

public:
generic <typename TSource, typename TKey, typename TElement>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TElement> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, Func<TSource, TElement> ^ elementSelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.Dictionary<TKey,TElement> ToDictionary<TSource,TKey,TElement> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, Func<TSource,TElement> elementSelector, System.Collections.Generic.IEqualityComparer<TKey> comparer);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> * Func<'Source, 'Element> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.Dictionary<'Key, 'Element>
<Extension()>
Public Function ToDictionary(Of TSource, TKey, TElement) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), elementSelector As Func(Of TSource, TElement), comparer As IEqualityComparer(Of TKey)) As Dictionary(Of TKey, TElement)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

TKey

keySelector によって返されるキーの型。The type of the key returned by keySelector.

TElement

elementSelector によって返される値の型。The type of the value returned by elementSelector.

パラメーター

source
IEnumerable<TSource>

Dictionary<TKey,TValue> の作成元の IEnumerable<T>An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

各要素からキーを抽出する関数。A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

各要素から結果の要素値を生成する変換関数。A transform function to produce a result element value from each element.

comparer
IEqualityComparer<TKey>

キーを比較する IEqualityComparer<T>An IEqualityComparer<T> to compare keys.

戻り値

Dictionary<TKey,TElement>

入力シーケンスから選択された TElement 型の値を格納する Dictionary<TKey,TValue>A Dictionary<TKey,TValue> that contains values of type TElement selected from the input sequence.

例外

sourcekeySelector、または elementSelector は、null です。source or keySelector or elementSelector is null.

- または --or- keySelectornull のキーを生成しています。keySelector produces a key that is null.

keySelector が 2 つの要素に対して重複するキーを生成しています。keySelector produces duplicate keys for two elements.

注釈

comparernull場合、キーの比較には既定の等値比較子 Default が使用されます。If comparer is null, the default equality comparer Default is used to compare keys.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)

指定されたキー セレクター関数に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TSource> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector);
public static System.Collections.Generic.Dictionary<TKey,TSource> ToDictionary<TSource,TKey> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> -> System.Collections.Generic.Dictionary<'Key, 'Source>
<Extension()>
Public Function ToDictionary(Of TSource, TKey) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey)) As Dictionary(Of TKey, TSource)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

TKey

keySelector によって返されるキーの型。The type of the key returned by keySelector.

パラメーター

source
IEnumerable<TSource>

Dictionary<TKey,TValue> の作成元の IEnumerable<T>An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

各要素からキーを抽出する関数。A function to extract a key from each element.

戻り値

Dictionary<TKey,TSource>

キーと値を格納している Dictionary<TKey,TValue>A Dictionary<TKey,TValue> that contains keys and values.

例外

source または keySelectornull です。source or keySelector is null.

- または --or- keySelectornull のキーを生成しています。keySelector produces a key that is null.

keySelector が 2 つの要素に対して重複するキーを生成しています。keySelector produces duplicate keys for two elements.

次のコード例は、ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) を使用して、キーセレクターを使用して Dictionary<TKey,TValue> を作成する方法を示しています。The following code example demonstrates how to use ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) to create a Dictionary<TKey,TValue> by using a key selector.

class Package
{
    public string Company { get; set; }
    public double Weight { get; set; }
    public long TrackingNumber { get; set; }
}

public static void ToDictionaryEx1()
{
    List<Package> packages =
        new List<Package>
            { new Package { Company = "Coho Vineyard", Weight = 25.2, TrackingNumber = 89453312L },
              new Package { Company = "Lucerne Publishing", Weight = 18.7, TrackingNumber = 89112755L },
              new Package { Company = "Wingtip Toys", Weight = 6.0, TrackingNumber = 299456122L },
              new Package { Company = "Adventure Works", Weight = 33.8, TrackingNumber = 4665518773L } };

    // Create a Dictionary of Package objects, 
    // using TrackingNumber as the key.
    Dictionary<long, Package> dictionary =
        packages.ToDictionary(p => p.TrackingNumber);

    foreach (KeyValuePair<long, Package> kvp in dictionary)
    {
        Console.WriteLine(
            "Key {0}: {1}, {2} pounds",
            kvp.Key,
            kvp.Value.Company,
            kvp.Value.Weight);
    }
}

/*
 This code produces the following output:

 Key 89453312: Coho Vineyard, 25.2 pounds
 Key 89112755: Lucerne Publishing, 18.7 pounds
 Key 299456122: Wingtip Toys, 6 pounds
 Key 4665518773: Adventure Works, 33.8 pounds
*/
Structure Package
    Public Company As String
    Public Weight As Double
    Public TrackingNumber As Long
End Structure

Sub ToDictionaryEx1()
    ' Create a list of Package values.
    Dim packages As New List(Of Package)(New Package() _
     {New Package With
      {.Company = "Coho Vineyard", .Weight = 25.2, .TrackingNumber = 89453312L},
      New Package With
      {.Company = "Lucerne Publishing", .Weight = 18.7, .TrackingNumber = 89112755L},
      New Package With
      {.Company = "Wingtip Toys", .Weight = 6.0, .TrackingNumber = 299456122L},
      New Package With
      {.Company = "Adventure Works", .Weight = 33.8, .TrackingNumber = 4665518773L}})

    ' Create a Dictionary that contains Package values, 
    ' using TrackingNumber as the key.
    Dim dict As Dictionary(Of Long, Package) =
    packages.ToDictionary(Function(p) p.TrackingNumber)

    ' Display the results.
    Dim output As New System.Text.StringBuilder
    For Each kvp As KeyValuePair(Of Long, Package) In dict
        output.AppendLine("Key " & kvp.Key & ": " &
                      kvp.Value.Company & ", " &
                      kvp.Value.Weight & " pounds")
    Next
    Console.WriteLine(output.ToString())
End Sub

' This code produces the following output:
'
' Key 89453312: Coho Vineyard, 25.2 pounds
' Key 89112755: Lucerne Publishing, 18.7 pounds
' Key 299456122: Wingtip Toys, 6 pounds
' Key 4665518773: Adventure Works, 33.8 pounds

注釈

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) メソッドでは、既定の等値比較子 Default を使用してキーを比較します。The ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) method uses the default equality comparer Default to compare keys.

ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)

指定されたキー セレクター関数およびキーの比較子に従って、Dictionary<TKey,TValue> から IEnumerable<T> を作成します。Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.

public:
generic <typename TSource, typename TKey>
[System::Runtime::CompilerServices::Extension]
 static System::Collections::Generic::Dictionary<TKey, TSource> ^ ToDictionary(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Collections.Generic.Dictionary<TKey,TSource> ToDictionary<TSource,TKey> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer);
static member ToDictionary : seq<'Source> * Func<'Source, 'Key> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Collections.Generic.Dictionary<'Key, 'Source>
<Extension()>
Public Function ToDictionary(Of TSource, TKey) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), comparer As IEqualityComparer(Of TKey)) As Dictionary(Of TKey, TSource)

型パラメーター

TSource

source の要素の型。The type of the elements of source.

TKey

keySelector によって返されるキーの型。The type of the keys returned by keySelector.

パラメーター

source
IEnumerable<TSource>

Dictionary<TKey,TValue> の作成元の IEnumerable<T>An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

各要素からキーを抽出する関数。A function to extract a key from each element.

comparer
IEqualityComparer<TKey>

キーを比較する IEqualityComparer<T>An IEqualityComparer<T> to compare keys.

戻り値

Dictionary<TKey,TSource>

キーと値を格納している Dictionary<TKey,TValue>A Dictionary<TKey,TValue> that contains keys and values.

例外

source または keySelectornull です。source or keySelector is null.

- または --or- keySelectornull のキーを生成しています。keySelector produces a key that is null.

keySelector が 2 つの要素に対して重複するキーを生成しています。keySelector produces duplicate keys for two elements.

注釈

comparernull場合、キーの比較には既定の等値比較子 Default が使用されます。If comparer is null, the default equality comparer Default is used to compare keys.

適用対象