Enumerable.ToDictionary Method

Definition

Overloads

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

Crea un objeto Dictionary<TKey,TValue> a partir de un objeto IEnumerable<T> según el selector de claves especificado y las funciones del selector de elementos.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>)

Crea un objeto Dictionary<TKey,TValue> a partir de un objeto IEnumerable<T> según una función del selector de claves especificada, un comparador y una función del selector de elementos.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>)

Crea una clase Dictionary<TKey,TValue> a partir de una interfaz IEnumerable<T> según una función del selector de claves especificada.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>)

Crea un objeto Dictionary<TKey,TValue> a partir de un objeto IEnumerable<T> según una función del selector de claves especificada y el comparador de claves.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>)

Crea un objeto Dictionary<TKey,TValue> a partir de un objeto IEnumerable<T> según el selector de claves especificado y las funciones del selector de elementos.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)

Type Parameters

TSource

Tipo de los elementos de source.The type of the elements of source.

TKey

Tipo de la clave devuelta por keySelector.The type of the key returned by keySelector.

TElement

Tipo de valor devuelto por elementSelector.The type of the value returned by elementSelector.

Parameters

source
IEnumerable<TSource>

IEnumerable<T> a partir del que se va a crear un Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Función para extraer una clave a partir de cada elemento.A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

Función de transformación que va a generar un valor de elemento de resultado a partir de cada elemento.A transform function to produce a result element value from each element.

Returns

Dictionary<TKey,TElement>

Dictionary<TKey,TValue> que contiene valores de tipo TElement seleccionados en la secuencia de entrada.A Dictionary<TKey,TValue> that contains values of type TElement selected from the input sequence.

Exceptions

source o keySelector o elementSelector es null.source or keySelector or elementSelector is null.

O bien-or- keySelector genera una clave cuyo valor es null.keySelector produces a key that is null.

keySelector genera claves duplicadas para dos elementos.keySelector produces duplicate keys for two elements.

Remarks

El método ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) usa el Default comparador de igualdad predeterminado para comparar claves.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>)

Crea un objeto Dictionary<TKey,TValue> a partir de un objeto IEnumerable<T> según una función del selector de claves especificada, un comparador y una función del selector de elementos.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)

Type Parameters

TSource

Tipo de los elementos de source.The type of the elements of source.

TKey

Tipo de la clave devuelta por keySelector.The type of the key returned by keySelector.

TElement

Tipo de valor devuelto por elementSelector.The type of the value returned by elementSelector.

Parameters

source
IEnumerable<TSource>

IEnumerable<T> a partir del que se va a crear un Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Función para extraer una clave a partir de cada elemento.A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

Función de transformación que va a generar un valor de elemento de resultado a partir de cada elemento.A transform function to produce a result element value from each element.

comparer
IEqualityComparer<TKey>

IEqualityComparer<T> para comparar claves.An IEqualityComparer<T> to compare keys.

Returns

Dictionary<TKey,TElement>

Dictionary<TKey,TValue> que contiene valores de tipo TElement seleccionados en la secuencia de entrada.A Dictionary<TKey,TValue> that contains values of type TElement selected from the input sequence.

Exceptions

source o keySelector o elementSelector es null.source or keySelector or elementSelector is null.

O bien-or- keySelector genera una clave cuyo valor es null.keySelector produces a key that is null.

keySelector genera claves duplicadas para dos elementos.keySelector produces duplicate keys for two elements.

Remarks

Si comparer es null, se utiliza el comparador de igualdad predeterminado Default para comparar las claves.If comparer is null, the default equality comparer Default is used to compare keys.

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

Crea una clase Dictionary<TKey,TValue> a partir de una interfaz IEnumerable<T> según una función del selector de claves especificada.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)

Type Parameters

TSource

Tipo de los elementos de source.The type of the elements of source.

TKey

Tipo de la clave devuelta por keySelector.The type of the key returned by keySelector.

Parameters

source
IEnumerable<TSource>

IEnumerable<T> a partir del que se va a crear un Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Función para extraer una clave a partir de cada elemento.A function to extract a key from each element.

Returns

Dictionary<TKey,TSource>

Dictionary<TKey,TValue> que contiene claves y valores.A Dictionary<TKey,TValue> that contains keys and values. Los valores de cada grupo están en el mismo orden que en source.The values within each group are in the same order as in source.

Exceptions

source o keySelector es null.source or keySelector is null.

O bien-or- keySelector genera una clave cuyo valor es null.keySelector produces a key that is null.

keySelector genera claves duplicadas para dos elementos.keySelector produces duplicate keys for two elements.

Examples

En el ejemplo de código siguiente se muestra cómo usar ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) para crear un Dictionary<TKey,TValue> mediante un selector de claves.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

Remarks

El método ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) usa el Default comparador de igualdad predeterminado para comparar claves.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>)

Crea un objeto Dictionary<TKey,TValue> a partir de un objeto IEnumerable<T> según una función del selector de claves especificada y el comparador de claves.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)

Type Parameters

TSource

Tipo de los elementos de source.The type of the elements of source.

TKey

Tipo de las claves devueltas por keySelector.The type of the keys returned by keySelector.

Parameters

source
IEnumerable<TSource>

IEnumerable<T> a partir del que se va a crear un Dictionary<TKey,TValue>.An IEnumerable<T> to create a Dictionary<TKey,TValue> from.

keySelector
Func<TSource,TKey>

Función para extraer una clave a partir de cada elemento.A function to extract a key from each element.

comparer
IEqualityComparer<TKey>

IEqualityComparer<T> para comparar claves.An IEqualityComparer<T> to compare keys.

Returns

Dictionary<TKey,TSource>

Dictionary<TKey,TValue> que contiene claves y valores.A Dictionary<TKey,TValue> that contains keys and values. Los valores de cada grupo están en el mismo orden que en source.The values within each group are in the same order as in source.

Exceptions

source o keySelector es null.source or keySelector is null.

O bien-or- keySelector genera una clave cuyo valor es null.keySelector produces a key that is null.

keySelector genera claves duplicadas para dos elementos.keySelector produces duplicate keys for two elements.

Remarks

Si comparer es null, se utiliza el comparador de igualdad predeterminado Default para comparar las claves.If comparer is null, the default equality comparer Default is used to compare keys.

Applies to