Array.FindIndex Metod

Definition

Överlagringar

Exempel

I följande kodexempel visas alla tre överlagringarna av den FindIndex generiska metoden. En matris med strängar skapas, som innehåller 8 dinosaurienamn, varav två (på position 1 och 5) slutar med "saurus". Kodexemplet definierar också en sökpredikatmetod med namnet EndsWithSaurus, som accepterar en strängparameter och returnerar ett booleskt värde som anger om indatasträngen slutar med "saurus".

Metodöverlagringen FindIndex<T>(T[], Predicate<T>) passerar matrisen från början och skickar varje element i tur och ordning till EndsWithSaurus metoden. Sökningen stoppas EndsWithSaurus när metoden returnerar true för elementet vid position 1.

Metodöverlagringen FindIndex<T>(T[], Int32, Predicate<T>) används för att söka i matrisen med början vid position 2 och fortsätta till slutet av matrisen. Den hittar elementet vid position 5. Slutligen används metodöverlagringen FindIndex<T>(T[], Int32, Int32, Predicate<T>) för att söka i intervallet med tre element som börjar vid position 2. Den returnerar -1 eftersom det inte finns några dinosaurienamn i det intervallet som slutar med "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.FindIndex(dinosaurs, EndsWithSaurus): {0}",
            Array.FindIndex(dinosaurs, EndsWithSaurus));

        Console.WriteLine(
            "\nArray.FindIndex(dinosaurs, 2, EndsWithSaurus): {0}",
            Array.FindIndex(dinosaurs, 2, EndsWithSaurus));

        Console.WriteLine(
            "\nArray.FindIndex(dinosaurs, 2, 3, EndsWithSaurus): {0}",
            Array.FindIndex(dinosaurs, 2, 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.FindIndex(dinosaurs, EndsWithSaurus): 1

Array.FindIndex(dinosaurs, 2, EndsWithSaurus): 5

Array.FindIndex(dinosaurs, 2, 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.FindIndex(dinosaurs, endsWithSaurus)
|> printfn "\nArray.FindIndex(dinosaurs, EndsWithSaurus): %i"

Array.FindIndex(dinosaurs, 2, endsWithSaurus)
|> printfn "\nArray.FindIndex(dinosaurs, 2, EndsWithSaurus): %i"

Array.FindIndex(dinosaurs, 2, 3, endsWithSaurus)
|> printfn "\nArray.FindIndex(dinosaurs, 2, 3, EndsWithSaurus): %i"


// This code example produces the following output:
//
//     Compsognathus
//     Amargasaurus
//     Oviraptor
//     Velociraptor
//     Deinonychus
//     Dilophosaurus
//     Gallimimus
//     Triceratops
//
//     Array.FindIndex(dinosaurs, EndsWithSaurus): 1
//
//     Array.FindIndex(dinosaurs, 2, EndsWithSaurus): 5
//
//     Array.FindIndex(dinosaurs, 2, 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.FindIndex(dinosaurs, AddressOf EndsWithSaurus): {0}", _
            Array.FindIndex(dinosaurs, AddressOf EndsWithSaurus))

        Console.WriteLine(vbLf & _
            "Array.FindIndex(dinosaurs, 2, AddressOf EndsWithSaurus): {0}", _
            Array.FindIndex(dinosaurs, 2, AddressOf EndsWithSaurus))

        Console.WriteLine(vbLf & _
            "Array.FindIndex(dinosaurs, 2, 3, AddressOf EndsWithSaurus): {0}", _
            Array.FindIndex(dinosaurs, 2, 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.FindIndex(dinosaurs, AddressOf EndsWithSaurus): 1
'
'Array.FindIndex(dinosaurs, 2, AddressOf EndsWithSaurus): 5
'
'Array.FindIndex(dinosaurs, 2, 3, AddressOf EndsWithSaurus): -1

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

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

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

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

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

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

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

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

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

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

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

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