Enumerable.ToLookup Enumerable.ToLookup Enumerable.ToLookup Enumerable.ToLookup Method

Definice

Vytvoří obecný Lookup<TKey,TElement> IEnumerable<T>z.Creates a generic Lookup<TKey,TElement> from an IEnumerable<T>.

Přetížení

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z v závislosti na zadaných funkcích selektoru klíče a voličů prvků.Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to specified key selector and element selector functions.

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z podle zadané funkce výběru klíče, porovnávací funkce a funkci selektor elementu.Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function, a comparer and an element selector function.

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z podle zadané funkce výběru klíče.Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function.

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z v závislosti na zadané funkci výběru klíče a porovnávací klávesu.Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function and key comparer.

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z v závislosti na zadaných funkcích selektoru klíče a voličů prvků.Creates a Lookup<TKey,TElement> 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::Linq::ILookup<TKey, TElement> ^ ToLookup(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, Func<TSource, TElement> ^ elementSelector);
public static System.Linq.ILookup<TKey,TElement> ToLookup<TSource,TKey,TElement> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, Func<TSource,TElement> elementSelector);
static member ToLookup : seq<'Source> * Func<'Source, 'Key> * Func<'Source, 'Element> -> System.Linq.ILookup<'Key, 'Element>
<Extension()>
Public Function ToLookup(Of TSource, TKey, TElement) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), elementSelector As Func(Of TSource, TElement)) As ILookup(Of TKey, TElement)

Parametry typu

TSource

Typ prvků source.The type of the elements of source.

TKey

Typ klíče vrácený keySelector.The type of the key returned by keySelector.

TElement

Typ hodnoty vrácené elementSelector.The type of the value returned by elementSelector.

Parametry

source
IEnumerable<TSource>

IEnumerable<T> ALookup<TKey,TElement> vytvořte z.The IEnumerable<T> to create a Lookup<TKey,TElement> from.

keySelector
Func<TSource,TKey>

Funkce pro extrakci klíče z každého elementu.A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

Transformační funkce pro vytvoření hodnoty elementu výsledku z každého elementu.A transform function to produce a result element value from each element.

Návraty

, Který obsahuje hodnoty typu TElement vybrané ze vstupní sekvence. Lookup<TKey,TElement>A Lookup<TKey,TElement> that contains values of type TElement selected from the input sequence.

Výjimky

sourcenebo keySelector je.elementSelector nullsource or keySelector or elementSelector is null.

Příklady

Následující příklad kódu ukazuje, jak použít ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) k Lookup<TKey,TElement> vytvoření pomocí funkce pro selektoru klíče a funkci selektor elementu.The following code example demonstrates how to use ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) to create a Lookup<TKey,TElement> by using a key selector function and an element selector function.

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

public static void ToLookupEx1()
{
    // Create a list of Packages.
    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 = "Contoso Pharmaceuticals", 
                  Weight = 9.3, TrackingNumber = 670053128L },
              new Package { Company = "Wide World Importers", 
                  Weight = 33.8, TrackingNumber = 4665518773L } };

    // Create a Lookup to organize the packages. 
    // Use the first character of Company as the key value.
    // Select Company appended to TrackingNumber 
    // as the element values of the Lookup.
    ILookup<char, string> lookup =
        packages
        .ToLookup(p => Convert.ToChar(p.Company.Substring(0, 1)),
                  p => p.Company + " " + p.TrackingNumber);

    // Iterate through each IGrouping in the Lookup.
    foreach (IGrouping<char, string> packageGroup in lookup)
    {
        // Print the key value of the IGrouping.
        Console.WriteLine(packageGroup.Key);
        // Iterate through each value in the 
        // IGrouping and print its value.
        foreach (string str in packageGroup)
            Console.WriteLine("    {0}", str);
    }
}

/*
 This code produces the following output:

 C
     Coho Vineyard 89453312
     Contoso Pharmaceuticals 670053128
 L
     Lucerne Publishing 89112755
 W
     Wingtip Toys 299456122
     Wide World Importers 4665518773
*/
Structure Package
    Public Company As String
    Public Weight As Double
    Public TrackingNumber As Long
End Structure

Sub ToLookupEx1()
    ' Create a list of Packages.
    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 = "Contoso Pharmaceuticals", .Weight = 9.3, .TrackingNumber = 670053128L},
      New Package With
      {.Company = "Wide World Importers", .Weight = 33.8, .TrackingNumber = 4665518773L}})

    ' Create a Lookup to organize the packages. 
    ' Use the first character of Company as the key value.
    ' Select Company appended to TrackingNumber 
    ' as the element values of the Lookup.
    Dim lookup As ILookup(Of Char, String) =
    packages.ToLookup(Function(p) _
                          Convert.ToChar(p.Company.Substring(0, 1)),
                      Function(p) _
                          p.Company & " " & p.TrackingNumber)

    Dim output As New System.Text.StringBuilder

    ' Iterate through each IGrouping in the Lookup.
    For Each packageGroup As IGrouping(Of Char, String) In lookup
        ' Print the key value of the IGrouping.
        output.AppendLine(packageGroup.Key)
        ' Iterate through each value in the IGrouping and print its value.
        For Each str As String In packageGroup
            output.AppendLine("   " & str)
        Next
    Next

    ' Select a group of packages by indexing directly into the Lookup.
    Dim cgroup As IEnumerable(Of String) = lookup("C"c)

    output.AppendLine(vbCrLf & "Packages from Company names that start with 'C':")
    For Each str As String In cgroup
        output.AppendLine(str)
    Next

    ' Display the output.
    MsgBox(output.ToString())
End Sub

' This code produces the following output:
'
' C
'    Coho Vineyard 89453312
'    Contoso Pharmaceuticals 670053128
' L
'    Lucerne Publishing 89112755
' W
'    Wingtip Toys 299456122
'    Wide World Importers 4665518773
'
' Packages from Company names that start with 'C':
' Coho Vineyard 89453312
' Contoso Pharmaceuticals 670053128

Poznámky

ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) MetodaLookup<TKey,TElement>vrátí, ke slovníku typu jeden-mnoho, který mapuje klíče na kolekce hodnot.The ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>) method returns a Lookup<TKey,TElement>, a one-to-many dictionary that maps keys to collections of values. Lookup<TKey,TElement> Liší seDictionary<TKey,TValue>od, který provádí mapování klíčů 1:1 na jednotlivé hodnoty.A Lookup<TKey,TElement> differs from a Dictionary<TKey,TValue>, which performs a one-to-one mapping of keys to single values.

Výchozí porovnávání Default rovnosti se používá k porovnání klíčů.The default equality comparer Default is used to compare keys.

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z podle zadané funkce výběru klíče, porovnávací funkce a funkci selektor elementu.Creates a Lookup<TKey,TElement> 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::Linq::ILookup<TKey, TElement> ^ ToLookup(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, Func<TSource, TElement> ^ elementSelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Linq.ILookup<TKey,TElement> ToLookup<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 ToLookup : seq<'Source> * Func<'Source, 'Key> * Func<'Source, 'Element> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Linq.ILookup<'Key, 'Element>
<Extension()>
Public Function ToLookup(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 ILookup(Of TKey, TElement)

Parametry typu

TSource

Typ prvků source.The type of the elements of source.

TKey

Typ klíče vrácený keySelector.The type of the key returned by keySelector.

TElement

Typ hodnoty vrácené elementSelector.The type of the value returned by elementSelector.

Parametry

source
IEnumerable<TSource>

IEnumerable<T> ALookup<TKey,TElement> vytvořte z.The IEnumerable<T> to create a Lookup<TKey,TElement> from.

keySelector
Func<TSource,TKey>

Funkce pro extrakci klíče z každého elementu.A function to extract a key from each element.

elementSelector
Func<TSource,TElement>

Transformační funkce pro vytvoření hodnoty elementu výsledku z každého elementu.A transform function to produce a result element value from each element.

comparer
IEqualityComparer<TKey>

IEqualityComparer<T> K porovnání klíčů.An IEqualityComparer<T> to compare keys.

Návraty

, Který obsahuje hodnoty typu TElement vybrané ze vstupní sekvence. Lookup<TKey,TElement>A Lookup<TKey,TElement> that contains values of type TElement selected from the input sequence.

Výjimky

sourcenebo keySelector je.elementSelector nullsource or keySelector or elementSelector is null.

Poznámky

ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>) MetodaLookup<TKey,TElement>vrátí, ke slovníku typu jeden-mnoho, který mapuje klíče na kolekce hodnot.The ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>) method returns a Lookup<TKey,TElement>, a one-to-many dictionary that maps keys to collections of values. Lookup<TKey,TElement> Liší seDictionary<TKey,TValue>od, který provádí mapování klíčů 1:1 na jednotlivé hodnoty.A Lookup<TKey,TElement> differs from a Dictionary<TKey,TValue>, which performs a one-to-one mapping of keys to single values.

Pokud comparer Default je null, použije se výchozí porovnávání rovnosti pro porovnávání klíčů.If comparer is null, the default equality comparer Default is used to compare keys.

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z podle zadané funkce výběru klíče.Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function.

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

Parametry typu

TSource

Typ prvků source.The type of the elements of source.

TKey

Typ klíče vrácený keySelector.The type of the key returned by keySelector.

Parametry

source
IEnumerable<TSource>

IEnumerable<T> ALookup<TKey,TElement> vytvořte z.The IEnumerable<T> to create a Lookup<TKey,TElement> from.

keySelector
Func<TSource,TKey>

Funkce pro extrakci klíče z každého elementu.A function to extract a key from each element.

Návraty

ILookup<TKey,TSource>

Lookup<TKey,TElement> Obsahující klíče a hodnoty.A Lookup<TKey,TElement> that contains keys and values.

Výjimky

sourcenebo keySelector je null.source or keySelector is null.

Poznámky

ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) MetodaLookup<TKey,TElement>vrátí, ke slovníku typu jeden-mnoho, který mapuje klíče na kolekce hodnot.The ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>) method returns a Lookup<TKey,TElement>, a one-to-many dictionary that maps keys to collections of values. Lookup<TKey,TElement> Liší seDictionary<TKey,TValue>od, který provádí mapování klíčů 1:1 na jednotlivé hodnoty.A Lookup<TKey,TElement> differs from a Dictionary<TKey,TValue>, which performs a one-to-one mapping of keys to single values.

Výchozí porovnávání Default rovnosti se používá k porovnání klíčů.The default equality comparer Default is used to compare keys.

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

Lookup<TKey,TElement> VytvoříIEnumerable<T> z v závislosti na zadané funkci výběru klíče a porovnávací klávesu.Creates a Lookup<TKey,TElement> 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::Linq::ILookup<TKey, TSource> ^ ToLookup(System::Collections::Generic::IEnumerable<TSource> ^ source, Func<TSource, TKey> ^ keySelector, System::Collections::Generic::IEqualityComparer<TKey> ^ comparer);
public static System.Linq.ILookup<TKey,TSource> ToLookup<TSource,TKey> (this System.Collections.Generic.IEnumerable<TSource> source, Func<TSource,TKey> keySelector, System.Collections.Generic.IEqualityComparer<TKey> comparer);
static member ToLookup : seq<'Source> * Func<'Source, 'Key> * System.Collections.Generic.IEqualityComparer<'Key> -> System.Linq.ILookup<'Key, 'Source>
<Extension()>
Public Function ToLookup(Of TSource, TKey) (source As IEnumerable(Of TSource), keySelector As Func(Of TSource, TKey), comparer As IEqualityComparer(Of TKey)) As ILookup(Of TKey, TSource)

Parametry typu

TSource

Typ prvků source.The type of the elements of source.

TKey

Typ klíče vrácený keySelector.The type of the key returned by keySelector.

Parametry

source
IEnumerable<TSource>

IEnumerable<T> ALookup<TKey,TElement> vytvořte z.The IEnumerable<T> to create a Lookup<TKey,TElement> from.

keySelector
Func<TSource,TKey>

Funkce pro extrakci klíče z každého elementu.A function to extract a key from each element.

comparer
IEqualityComparer<TKey>

IEqualityComparer<T> K porovnání klíčů.An IEqualityComparer<T> to compare keys.

Návraty

ILookup<TKey,TSource>

Lookup<TKey,TElement> Obsahující klíče a hodnoty.A Lookup<TKey,TElement> that contains keys and values.

Výjimky

sourcenebo keySelector je null.source or keySelector is null.

Poznámky

ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>) MetodaLookup<TKey,TElement>vrátí, ke slovníku typu jeden-mnoho, který mapuje klíče na kolekce hodnot.The ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>) method returns a Lookup<TKey,TElement>, a one-to-many dictionary that maps keys to collections of values. A Lookup<TKey,TElement> se liší od typu Dictionary<TKey,TValue>, který provádí mapování klíčů 1:1 na jednotlivé hodnoty.A Lookup<TKey,TElement> is different to a Dictionary<TKey,TValue>, which performs a one-to-one mapping of keys to single values.

Pokud comparer Default je null, použije se výchozí porovnávání rovnosti pro porovnávání klíčů.If comparer is null, the default equality comparer Default is used to compare keys.

Platí pro