Array.FindLast<T>(T[], Predicate<T>) メソッド

public:
generic <typename T>
 static T FindLast(cli::array <T> ^ array, Predicate<T> ^ match);

public static T FindLast<T> (T[] array, Predicate<T> match);

public static T? FindLast<T> (T[] array, Predicate<T> match);

static member FindLast : 'T[] * Predicate<'T> -> 'T

Public Shared Function FindLast(Of T) (array As T(), match As Predicate(Of T)) As T

型パラメーター

パラメーター

戻り値

指定した述語で定義されている条件に一致する最後の要素 (見つかった場合)。それ以外の場合は、型の既定値 T。

例外

例

次のコード例は、ジェネリック メソッドの Find、FindLast、および FindAll を示しています。 8 つの恐竜名を含む文字列の配列が作成され、そのうちの 2 つ (位置 1 と 5) は "saurus" で終わる。 このコード例では、EndsWithSaurusという名前の検索述語メソッドも定義します。このメソッドは文字列パラメーターを受け取り、入力文字列が "saurus" で終わるかどうかを示すブール値を返します。

Find ジェネリック メソッドは、配列を最初から走査し、各要素を EndsWithSaurus メソッドに順番に渡します。 EndsWithSaurus メソッドが要素 "Amargasaurus" の true を返すと、検索は停止します。

FindLast ジェネリック メソッドは、配列を末尾から後方に検索するために使用されます。 位置 5 で要素 "Dilophosaurus" を検出します。 FindAll ジェネリック メソッドは、"saurus" で終わるすべての要素を含む配列を返すために使用されます。 要素が表示されます。

コード例では、ジェネリック メソッドの Exists と TrueForAll も示します。

using namespace System;

public ref class DinoDiscoverySet
{
public:
    static void Main()
    {
        array<String^>^ dinosaurs =
        {
            "Compsognathus", "Amargasaurus", "Oviraptor",
            "Velociraptor",  "Deinonychus",  "Dilophosaurus",
            "Gallimimus",    "Triceratops"
        };

        DinoDiscoverySet^ GoMesozoic = gcnew DinoDiscoverySet(dinosaurs);

        GoMesozoic->DiscoverAll();
        GoMesozoic->DiscoverByEnding("saurus");
    }

    DinoDiscoverySet(array<String^>^ items)
    {
        dinosaurs = items;
    }

    void DiscoverAll()
    {
        Console::WriteLine();
        for each(String^ dinosaur in dinosaurs)
        {
            Console::WriteLine(dinosaur);
        }
    }

    void DiscoverByEnding(String^ Ending)
    {
        Predicate<String^>^ dinoType;

        if (Ending->ToLower() == "raptor")
        {
            dinoType =
                gcnew Predicate<String^>(&DinoDiscoverySet::EndsWithRaptor);
        }
        else if (Ending->ToLower() == "tops")
        {
            dinoType =
                gcnew Predicate<String^>(&DinoDiscoverySet::EndsWithTops);
        }
        else if (Ending->ToLower() == "saurus")
        {
            dinoType =
                gcnew Predicate<String^>(&DinoDiscoverySet::EndsWithSaurus);
        }
        else
        {
            dinoType =
                gcnew Predicate<String^>(&DinoDiscoverySet::EndsWithSaurus);
        }

        Console::WriteLine(
            "\nArray::Exists(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array::Exists(dinosaurs, dinoType));

        Console::WriteLine(
            "\nArray::TrueForAll(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array::TrueForAll(dinosaurs, dinoType));

        Console::WriteLine(
            "\nArray::Find(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array::Find(dinosaurs, dinoType));

        Console::WriteLine(
            "\nArray::FindLast(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array::FindLast(dinosaurs, dinoType));

        Console::WriteLine(
            "\nArray::FindAll(dinosaurs, \"{0}\"):", Ending);

        array<String^>^ subArray =
            Array::FindAll(dinosaurs, dinoType);

        for each(String^ dinosaur in subArray)
        {
            Console::WriteLine(dinosaur);
        }
    }

private:
    array<String^>^ dinosaurs;

    // Search predicate returns true if a string ends in "saurus".
    static bool EndsWithSaurus(String^ s)
    {
        if ((s->Length > 5) &&
            (s->Substring(s->Length - 6)->ToLower() == "saurus"))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    // Search predicate returns true if a string ends in "raptor".
    static bool EndsWithRaptor(String^ s)
    {
        if ((s->Length > 5) &&
            (s->Substring(s->Length - 6)->ToLower() == "raptor"))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    // Search predicate returns true if a string ends in "tops".
    static bool EndsWithTops(String^ s)
    {
        if ((s->Length > 3) &&
            (s->Substring(s->Length - 4)->ToLower() == "tops"))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
};

int main()
{
    DinoDiscoverySet::Main();
}

/* This code example produces the following output:

Compsognathus
Amargasaurus
Oviraptor
Velociraptor
Deinonychus
Dilophosaurus
Gallimimus
Triceratops

Array.Exists(dinosaurs, "saurus"): True

Array.TrueForAll(dinosaurs, "saurus"): False

Array.Find(dinosaurs, "saurus"): Amargasaurus

Array.FindLast(dinosaurs, "saurus"): Dilophosaurus

Array.FindAll(dinosaurs, "saurus"):
Amargasaurus
Dilophosaurus
*/

using System;

public class DinoDiscoverySet
{
    public static void Main()
    {
        string[] dinosaurs =
        {
            "Compsognathus", "Amargasaurus", "Oviraptor",
            "Velociraptor",  "Deinonychus",  "Dilophosaurus",
            "Gallimimus",    "Triceratops"
        };

        DinoDiscoverySet GoMesozoic = new DinoDiscoverySet(dinosaurs);

        GoMesozoic.DiscoverAll();
        GoMesozoic.DiscoverByEnding("saurus");
    }

    private string[] dinosaurs;

    public DinoDiscoverySet(string[] items)
    {
        dinosaurs = items;
    }

    public void DiscoverAll()
    {
        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }
    }

    public void DiscoverByEnding(string Ending)
    {
        Predicate<string> dinoType;

        switch (Ending.ToLower())
        {
            case "raptor":
                dinoType = EndsWithRaptor;
                break;
            case "tops":
                dinoType = EndsWithTops;
                break;
            case "saurus":
            default:
                dinoType = EndsWithSaurus;
                break;
        }
        Console.WriteLine(
            "\nArray.Exists(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array.Exists(dinosaurs, dinoType));

        Console.WriteLine(
            "\nArray.TrueForAll(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array.TrueForAll(dinosaurs, dinoType));

        Console.WriteLine(
            "\nArray.Find(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array.Find(dinosaurs, dinoType));

        Console.WriteLine(
            "\nArray.FindLast(dinosaurs, \"{0}\"): {1}",
            Ending,
            Array.FindLast(dinosaurs, dinoType));

        Console.WriteLine(
            "\nArray.FindAll(dinosaurs, \"{0}\"):", Ending);

        string[] subArray =
            Array.FindAll(dinosaurs, dinoType);

        foreach(string dinosaur in subArray)
        {
            Console.WriteLine(dinosaur);
        }
    }

    // Search predicate returns true if a string ends in "saurus".
    private bool EndsWithSaurus(string s)
    {
        if ((s.Length > 5) &&
            (s.Substring(s.Length - 6).ToLower() == "saurus"))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    // Search predicate returns true if a string ends in "raptor".
    private bool EndsWithRaptor(String s)
    {
        if ((s.Length > 5) &&
            (s.Substring(s.Length - 6).ToLower() == "raptor"))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    // Search predicate returns true if a string ends in "tops".
    private bool EndsWithTops(String s)
    {
        if ((s.Length > 3) &&
            (s.Substring(s.Length - 4).ToLower() == "tops"))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
}

/* This code example produces the following output:

Compsognathus
Amargasaurus
Oviraptor
Velociraptor
Deinonychus
Dilophosaurus
Gallimimus
Triceratops

Array.Exists(dinosaurs, "saurus"): True

Array.TrueForAll(dinosaurs, "saurus"): False

Array.Find(dinosaurs, "saurus"): Amargasaurus

Array.FindLast(dinosaurs, "saurus"): Dilophosaurus

Array.FindAll(dinosaurs, "saurus"):
Amargasaurus
Dilophosaurus
*/

open System

// Search predicate returns true if a string ends in "saurus".
let endsWithSaurus (s: string) =
    s.Length > 5 && s.Substring(s.Length - 6).ToLower() = "saurus"

// Search predicate returns true if a string ends in "raptor".
let endsWithRaptor (s: string) =
    s.Length > 5 && s.Substring(s.Length - 6).ToLower() = "raptor"

// Search predicate returns true if a string ends in "tops".
let endsWithTops (s: string) =
    s.Length > 3 && s.Substring(s.Length - 4).ToLower() = "tops"

type DinoDiscoverySet =
    { Dinosaurs: string [] }

    member this.DiscoverAll() =
        printfn ""
        for dino in this.Dinosaurs do
            printfn $"{dino}"

    member this.DiscoverByEnding(ending: string) =
        let dinoType =
            match ending.ToLower() with
            | "raptor" -> endsWithRaptor
            | "tops" -> endsWithTops
            | "saurus" | _ -> endsWithSaurus

        Array.Exists(this.Dinosaurs, dinoType)
        |> printfn "\nArray.Exists(dinosaurs, \"%s\"): %b" ending

        Array.TrueForAll(this.Dinosaurs, dinoType)
        |> printfn "\nArray.TrueForAll(dinosaurs, \"%s\"): %b" ending

        Array.Find(this.Dinosaurs, dinoType)
        |> printfn "\nArray.Find(dinosaurs, \"%s\"): %s" ending

        Array.FindLast(this.Dinosaurs, dinoType)
        |> printfn "\nArray.FindLast(dinosaurs, \"%s\"): %s" ending

        printfn $"\nArray.FindAll(dinosaurs, \"{ending}\"):"
        for dinosaur in Array.FindAll(this.Dinosaurs, dinoType) do
            printfn $"{dinosaur}"

let dinosaurs =
    [| "Compsognathus"; "Amargasaurus"; "Oviraptor"
       "Velociraptor"; "Deinonychus"; "Dilophosaurus"
       "Gallimimus"; "Triceratops" |]

let goMesozoic = { Dinosaurs = dinosaurs }

goMesozoic.DiscoverAll()
goMesozoic.DiscoverByEnding "saurus"


// This code example produces the following output:
//     Compsognathus
//     Amargasaurus
//     Oviraptor
//     Velociraptor
//     Deinonychus
//     Dilophosaurus
//     Gallimimus
//     Triceratops
//
//     Array.Exists(dinosaurs, "saurus"): true
//
//     Array.TrueForAll(dinosaurs, "saurus"): false
//
//     Array.Find(dinosaurs, "saurus"): Amargasaurus
//
//     Array.FindLast(dinosaurs, "saurus"): Dilophosaurus
//
//     Array.FindAll(dinosaurs, "saurus"):
//     Amargasaurus
//     Dilophosaurus

Public Class DinoDiscoverySet

    Public Shared Sub Main()
        Dim dinosaurs() As String = { "Compsognathus", _
            "Amargasaurus",   "Oviraptor",      "Velociraptor", _
            "Deinonychus",    "Dilophosaurus",  "Gallimimus", _
            "Triceratops" }

        Dim GoMesozoic As New DinoDiscoverySet(dinosaurs)

        GoMesozoic.DiscoverAll()
        GoMesozoic.DiscoverByEnding("saurus")
    End Sub

    Private dinosaurs As String()

    Public Sub New(items() As String)
        dinosaurs = items
    End Sub

    Public Sub DiscoverAll()
        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next dinosaur
    End Sub

    Public Sub DiscoverByEnding(Ending As String)
        Dim dinoType As Predicate(Of String)

        Select Case Ending.ToLower()
            Case "raptor"
                dinoType = AddressOf EndsWithRaptor
            Case "tops"
                dinoType = AddressOf EndsWithTops
            Case "saurus"
                dinoType = AddressOf EndsWithSaurus
            Case Else
                dinoType = AddressOf EndsWithSaurus
        End Select

        Console.WriteLine(Environment.NewLine + _
            "Array.Exists(dinosaurs, ""{0}""): {1}", _
            Ending, _
            Array.Exists(dinosaurs, dinoType))

        Console.WriteLine(Environment.NewLine + _
            "Array.TrueForAll(dinosaurs, ""{0}""): {1}", _
            Ending, _
            Array.TrueForAll(dinosaurs, dinoType))

        Console.WriteLine(Environment.NewLine + _
            "Array.Find(dinosaurs, ""{0}""): {1}", _
            Ending, _
            Array.Find(dinosaurs, dinoType))

        Console.WriteLine(Environment.NewLine + _
            "Array.FindLast(dinosaurs, ""{0}""): {1}", _
            Ending, _
            Array.FindLast(dinosaurs, dinoType))

        Console.WriteLine(Environment.NewLine + _
            "Array.FindAll(dinosaurs, ""{0}""):", Ending)

        Dim subArray() As String = _
            Array.FindAll(dinosaurs, dinoType)

        For Each dinosaur As String In subArray
            Console.WriteLine(dinosaur)
        Next dinosaur
    End Sub

    ' Search predicate returns true if a string ends in "saurus".
    Private Function EndsWithSaurus(s As String) As Boolean
        ' AndAlso prevents evaluation of the second Boolean
        ' expression if the string is so short that an error
        ' would occur.
        If (s.Length > 5) AndAlso _
            (s.ToLower().EndsWith("saurus")) Then
            Return True
        Else
            Return False
        End If
    End Function

    ' Search predicate returns true if a string ends in "raptor".
    Private Function EndsWithRaptor(s As String) As Boolean
        ' AndAlso prevents evaluation of the second Boolean
        ' expression if the string is so short that an error
        ' would occur.
        If (s.Length > 5) AndAlso _
            (s.ToLower().EndsWith("raptor")) Then
            Return True
        Else
            Return False
        End If
    End Function

    ' Search predicate returns true if a string ends in "tops".
    Private Function EndsWithTops(s As String) As Boolean
        ' AndAlso prevents evaluation of the second Boolean
        ' expression if the string is so short that an error
        ' would occur.
        If (s.Length > 3) AndAlso _
            (s.ToLower().EndsWith("tops")) Then
            Return True
        Else
            Return False
        End If
    End Function
End Class

' This code example produces the following output:
'
' Compsognathus
' Amargasaurus
' Oviraptor
' Velociraptor
' Deinonychus
' Dilophosaurus
' Gallimimus
' Triceratops
'
' Array.Exists(dinosaurs, "saurus"): True
'
' Array.TrueForAll(dinosaurs, "saurus"): False
'
' Array.Find(dinosaurs, "saurus"): Amargasaurus
'
' Array.FindLast(dinosaurs, "saurus"): Dilophosaurus
'
' Array.FindAll(dinosaurs, "saurus"):
' Amargasaurus
' Dilophosaurus

注釈

Predicate<T> は、渡されたオブジェクトがデリゲートで定義されている条件と一致する場合に true を返すメソッドへのデリゲートです。 array の要素は、Predicate<T>に個別に渡され、最後の要素から始まり、最初の要素で終わる Array内で後方に移動します。 一致が見つかると、処理が停止します。

このメソッドは O(n) 演算であり、ここで n は arrayの Length です。

適用対象

こちらもご覧ください

• Exists<T>(T[], Predicate<T>)
• Find<T>(T[], Predicate<T>)
• FindAll<T>(T[], Predicate<T>)
• BinarySearch
• IndexOf
• LastIndexOf
• Predicate<T>