Array.FindLastIndex Méthode

Définition

Surcharges

Exemples

L’exemple de code suivant illustre les trois surcharges de la FindLastIndex méthode générique. Un tableau de chaînes est créé, contenant 8 noms de dinosaures, dont deux (aux positions 1 et 5) se terminent par « saurus ». L’exemple de code définit également une méthode de prédicat de recherche nommée EndsWithSaurus, qui accepte un paramètre de chaîne et retourne une valeur booléenne indiquant si la chaîne d’entrée se termine par « saurus ».

La FindLastIndex<T>(T[], Predicate<T>) surcharge de méthode traverse le tableau vers l’arrière de la fin, en passant à son tour chaque élément à la EndsWithSaurus méthode. La recherche s’arrête lorsque la EndsWithSaurus méthode retourne true l’élément à la position 5.

La FindLastIndex<T>(T[], Int32, Predicate<T>) surcharge de méthode est utilisée pour rechercher le tableau à partir de la position 4 et passer en arrière au début du tableau. Il trouve l’élément à la position 1. Enfin, la FindLastIndex<T>(T[], Int32, Int32, Predicate<T>) surcharge de méthode est utilisée pour rechercher la plage de trois éléments commençant à la position 4 et en arrière (autrement dit, les éléments 4, 3 et 2). Elle retourne -1 parce qu’il n’y a pas de noms de dinosaures dans cette plage qui se terminent par « saurus ».

using System;

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

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

        Console.WriteLine(
            "\nArray.FindLastIndex(dinosaurs, EndsWithSaurus): {0}",
            Array.FindLastIndex(dinosaurs, EndsWithSaurus));

        Console.WriteLine(
            "\nArray.FindLastIndex(dinosaurs, 4, EndsWithSaurus): {0}",
            Array.FindLastIndex(dinosaurs, 4, EndsWithSaurus));

        Console.WriteLine(
            "\nArray.FindLastIndex(dinosaurs, 4, 3, EndsWithSaurus): {0}",
            Array.FindLastIndex(dinosaurs, 4, 3, EndsWithSaurus));
    }

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

/* This code example produces the following output:

Compsognathus
Amargasaurus
Oviraptor
Velociraptor
Deinonychus
Dilophosaurus
Gallimimus
Triceratops

Array.FindLastIndex(dinosaurs, EndsWithSaurus): 5

Array.FindLastIndex(dinosaurs, 4, EndsWithSaurus): 1

Array.FindLastIndex(dinosaurs, 4, 3, EndsWithSaurus): -1
 */

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"

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

printfn ""
for dino in dinosaurs do
    printfn $"{dino}"

Array.FindLastIndex(dinosaurs, endsWithSaurus)
|> printfn "\nArray.FindLastIndex(dinosaurs, EndsWithSaurus): %i"

Array.FindLastIndex(dinosaurs, 4, endsWithSaurus)
|> printfn "\nArray.FindLastIndex(dinosaurs, 4, EndsWithSaurus): %i"

Array.FindLastIndex(dinosaurs, 4, 3, endsWithSaurus)
|> printfn "\nArray.FindLastIndex(dinosaurs, 4, 3, EndsWithSaurus): %i"


// This code example produces the following output:
//
//     Compsognathus
//     Amargasaurus
//     Oviraptor
//     Velociraptor
//     Deinonychus
//     Dilophosaurus
//     Gallimimus
//     Triceratops
//
//     Array.FindLastIndex(dinosaurs, EndsWithSaurus): 5
//
//     Array.FindLastIndex(dinosaurs, 4, EndsWithSaurus): 1
//
//     Array.FindLastIndex(dinosaurs, 4, 3, EndsWithSaurus): -1

Public Class Example

    Public Shared Sub Main()

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

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "Array.FindLastIndex(dinosaurs, AddressOf EndsWithSaurus): {0}", _
            Array.FindLastIndex(dinosaurs, AddressOf EndsWithSaurus))

        Console.WriteLine(vbLf & _
            "Array.FindLastIndex(dinosaurs, 4, AddressOf EndsWithSaurus): {0}", _
            Array.FindLastIndex(dinosaurs, 4, AddressOf EndsWithSaurus))

        Console.WriteLine(vbLf & _
            "Array.FindLastIndex(dinosaurs, 4, 3, AddressOf EndsWithSaurus): {0}", _
            Array.FindLastIndex(dinosaurs, 4, 3, AddressOf EndsWithSaurus))

    End Sub

    ' Search predicate returns true if a string ends in "saurus".
    Private Shared Function EndsWithSaurus(ByVal 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.Substring(s.Length - 6).ToLower() = "saurus") 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.FindLastIndex(dinosaurs, AddressOf EndsWithSaurus): 5
'
'Array.FindLastIndex(dinosaurs, 4, AddressOf EndsWithSaurus): 1
'
'Array.FindLastIndex(dinosaurs, 4, 3, AddressOf EndsWithSaurus): -1

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

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

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

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

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

public static int FindLastIndex<T>(T[] array, int startIndex, Predicate<T> match);

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

Public Shared Function FindLastIndex(Of T) (array As T(), startIndex As Integer, match As Predicate(Of T)) As Integer

public:
generic <typename T>
 static int FindLastIndex(cli::array <T> ^ array, int startIndex, int count, Predicate<T> ^ match);

public static int FindLastIndex<T>(T[] array, int startIndex, int count, Predicate<T> match);

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

Public Shared Function FindLastIndex(Of T) (array As T(), startIndex As Integer, count As Integer, match As Predicate(Of T)) As Integer