ArrayList.LastIndexOf Metódus

Definíció

Névtér:

System.Collections

Szerelvények:

netstandard.dll, System.Runtime.dll

Egy érték utolsó előfordulásának nulla alapú indexét adja vissza a ArrayList benne vagy egy részben.

Túlterhelések

Name	Description
LastIndexOf(Object)	Megkeresi a megadott Object értéket, és a teljes utolsó ArrayListelőfordulás nulla alapú indexét adja vissza.
LastIndexOf(Object, Int32)	Megkeresi a megadott Object értéket, és visszaadja az utolsó előfordulás nullaalapú indexét az elemek tartományán belül, amely az ArrayList első elemtől a megadott indexig terjed.
LastIndexOf(Object, Int32, Int32)	Megkeresi a megadott Object értéket, és visszaadja az utolsó előfordulás nulla alapú indexét azon elemek tartományán belül, amelyek a ArrayList megadott számú elemet tartalmazzák, és a megadott indexben végződnek.

LastIndexOf(Object)

Forrás:

ArrayList.cs

Megkeresi a megadott Object értéket, és a teljes utolsó ArrayListelőfordulás nulla alapú indexét adja vissza.

public:
 virtual int LastIndexOf(System::Object ^ value);

public virtual int LastIndexOf(object? value);

abstract member LastIndexOf : obj -> int
override this.LastIndexOf : obj -> int

Public Overridable Function LastIndexOf (value As Object) As Integer

Paraméterek

value

Object

A Object keresendő ArrayList. Az érték lehet null.

Válaszok

Int32

A teljes value, ha megtalálható; egyébként -1 utolsó előfordulásának ArrayList nulla alapú indexe.

Példák

Az alábbi példakód bemutatja, hogyan határozható meg egy adott elem utolsó előfordulásának indexe.

using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList with three elements of the same value.
      ArrayList myAL = new ArrayList();
      myAL.Add( "the" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumps" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );
      myAL.Add( "in" );
      myAL.Add( "the" );
      myAL.Add( "barn" );

      // Displays the values of the ArrayList.
      Console.WriteLine( "The ArrayList contains the following values:" );
      PrintIndexAndValues( myAL );

      // Searches for the last occurrence of the duplicated value.
      string myString = "the";
      int myIndex = myAL.LastIndexOf( myString );
      Console.WriteLine( "The last occurrence of \"{0}\" is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in the first section of the ArrayList.
      myIndex = myAL.LastIndexOf( myString, 8 );
      Console.WriteLine( "The last occurrence of \"{0}\" between the start and index 8 is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in a section of the ArrayList.  Note that the start index is greater than the end index because the search is done backward.
      myIndex = myAL.LastIndexOf( myString, 10, 6 );
      Console.WriteLine( "The last occurrence of \"{0}\" between index 10 and index 5 is at index {1}.", myString, myIndex );
   }

   public static void PrintIndexAndValues( IEnumerable myList )  {
      int i = 0;
      foreach ( Object obj in myList )
         Console.WriteLine( "   [{0}]:    {1}", i++, obj );
      Console.WriteLine();
   }
}


/*
This code produces the following output.

The ArrayList contains the following values:
   [0]:    the
   [1]:    quick
   [2]:    brown
   [3]:    fox
   [4]:    jumps
   [5]:    over
   [6]:    the
   [7]:    lazy
   [8]:    dog
   [9]:    in
   [10]:    the
   [11]:    barn

The last occurrence of "the" is at index 10.
The last occurrence of "the" between the start and index 8 is at index 6.
The last occurrence of "the" between index 10 and index 5 is at index 10.
*/

Imports System.Collections

Public Class SamplesArrayList
   
   Public Shared Sub Main()
      
      ' Creates and initializes a new ArrayList with three elements of the same value.
      Dim myAL As New ArrayList()
      myAL.Add("the")
      myAL.Add("quick")
      myAL.Add("brown")
      myAL.Add("fox")
      myAL.Add("jumps")
      myAL.Add("over")
      myAL.Add("the")
      myAL.Add("lazy")
      myAL.Add("dog")
      myAL.Add("in")
      myAL.Add("the")
      myAL.Add("barn")
      
      ' Displays the values of the ArrayList.
      Console.WriteLine("The ArrayList contains the following values:")
      PrintIndexAndValues(myAL)
      
      ' Searches for the last occurrence of the duplicated value.
      Dim myString As [String] = "the"
      Dim myIndex As Integer = myAL.LastIndexOf(myString)
      Console.WriteLine("The last occurrence of ""{0}"" is at index {1}.", myString, myIndex)
      
      ' Searches for the last occurrence of the duplicated value in the first section of the ArrayList.
      myIndex = myAL.LastIndexOf(myString, 8)
      Console.WriteLine("The last occurrence of ""{0}"" between the start and index 8 is at index {1}.", myString, myIndex)
      
      ' Searches for the last occurrence of the duplicated value in a section of the ArrayList.  Note that the start index is greater than the end index because the search is done backward.
      myIndex = myAL.LastIndexOf(myString, 10, 6)
      Console.WriteLine("The last occurrence of ""{0}"" between index 10 and index 5 is at index {1}.", myString, myIndex)
   End Sub
   
   
   Public Shared Sub PrintIndexAndValues(myList As IEnumerable)
      Dim i as Integer
      Dim obj As [Object]
      For Each obj In  myList
         Console.WriteLine("   [{0}]:    {1}", i, obj)
         i = i + 1
      Next obj
      Console.WriteLine()
   End Sub

End Class

' This code produces the following output.
'
' The ArrayList contains the following values:
'    [0]:    the
'    [1]:    quick
'    [2]:    brown
'    [3]:    fox
'    [4]:    jumps
'    [5]:    over
'    [6]:    the
'    [7]:    lazy
'    [8]:    dog
'    [9]:    in
'    [10]:    the
'    [11]:    barn
'
' The last occurrence of "the" is at index 10.
' The last occurrence of "the" between the start and index 8 is at index 6.
' The last occurrence of "the" between index 10 and index 5 is at index 10.

Megjegyzések

A ArrayList rendszer az utolsó elemtől kezdve visszafelé keres, és az első elemnél végződik.

Ez a módszer lineáris keresést végez; ezért ez a módszer egy O(n) művelet, ahol n van Count.

Ez a metódus a gyűjtemény objektumait és Equals metódusait CompareToitem használja annak meghatározására, hogy létezik-e elem.

Lásd még

• IndexOf(Object)
• Contains(Object)
• Culture-Insensitive sztringműveletek végrehajtása gyűjteményekben

LastIndexOf(Object, Int32)

Forrás:

ArrayList.cs

Megkeresi a megadott Object értéket, és visszaadja az utolsó előfordulás nullaalapú indexét az elemek tartományán belül, amely az ArrayList első elemtől a megadott indexig terjed.

public:
 virtual int LastIndexOf(System::Object ^ value, int startIndex);

public virtual int LastIndexOf(object? value, int startIndex);

abstract member LastIndexOf : obj * int -> int
override this.LastIndexOf : obj * int -> int

Public Overridable Function LastIndexOf (value As Object, startIndex As Integer) As Integer

Paraméterek

value

Object

A Object keresendő ArrayList. Az érték lehet null.

startIndex

Int32

A visszamenőleges keresés nulla alapú kezdőindexe.

Válaszok

Int32

Az elemek tartományán belüli utolsó előfordulás nulla alapú indexe value , amely az ArrayList első elemtől az – ha megtalálható – értékig startIndexterjed, ellenkező esetben –1.

Kivételek

ArgumentOutOfRangeException

startIndexkívül esik az érvényes indexek tartományán.ArrayList

Példák

Az alábbi példakód bemutatja, hogyan határozható meg egy adott elem utolsó előfordulásának indexe.

using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList with three elements of the same value.
      ArrayList myAL = new ArrayList();
      myAL.Add( "the" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumps" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );
      myAL.Add( "in" );
      myAL.Add( "the" );
      myAL.Add( "barn" );

      // Displays the values of the ArrayList.
      Console.WriteLine( "The ArrayList contains the following values:" );
      PrintIndexAndValues( myAL );

      // Searches for the last occurrence of the duplicated value.
      string myString = "the";
      int myIndex = myAL.LastIndexOf( myString );
      Console.WriteLine( "The last occurrence of \"{0}\" is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in the first section of the ArrayList.
      myIndex = myAL.LastIndexOf( myString, 8 );
      Console.WriteLine( "The last occurrence of \"{0}\" between the start and index 8 is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in a section of the ArrayList.  Note that the start index is greater than the end index because the search is done backward.
      myIndex = myAL.LastIndexOf( myString, 10, 6 );
      Console.WriteLine( "The last occurrence of \"{0}\" between index 10 and index 5 is at index {1}.", myString, myIndex );
   }

   public static void PrintIndexAndValues( IEnumerable myList )  {
      int i = 0;
      foreach ( Object obj in myList )
         Console.WriteLine( "   [{0}]:    {1}", i++, obj );
      Console.WriteLine();
   }
}


/*
This code produces the following output.

The ArrayList contains the following values:
   [0]:    the
   [1]:    quick
   [2]:    brown
   [3]:    fox
   [4]:    jumps
   [5]:    over
   [6]:    the
   [7]:    lazy
   [8]:    dog
   [9]:    in
   [10]:    the
   [11]:    barn

The last occurrence of "the" is at index 10.
The last occurrence of "the" between the start and index 8 is at index 6.
The last occurrence of "the" between index 10 and index 5 is at index 10.
*/

Imports System.Collections

Public Class SamplesArrayList
   
   Public Shared Sub Main()
      
      ' Creates and initializes a new ArrayList with three elements of the same value.
      Dim myAL As New ArrayList()
      myAL.Add("the")
      myAL.Add("quick")
      myAL.Add("brown")
      myAL.Add("fox")
      myAL.Add("jumps")
      myAL.Add("over")
      myAL.Add("the")
      myAL.Add("lazy")
      myAL.Add("dog")
      myAL.Add("in")
      myAL.Add("the")
      myAL.Add("barn")
      
      ' Displays the values of the ArrayList.
      Console.WriteLine("The ArrayList contains the following values:")
      PrintIndexAndValues(myAL)
      
      ' Searches for the last occurrence of the duplicated value.
      Dim myString As [String] = "the"
      Dim myIndex As Integer = myAL.LastIndexOf(myString)
      Console.WriteLine("The last occurrence of ""{0}"" is at index {1}.", myString, myIndex)
      
      ' Searches for the last occurrence of the duplicated value in the first section of the ArrayList.
      myIndex = myAL.LastIndexOf(myString, 8)
      Console.WriteLine("The last occurrence of ""{0}"" between the start and index 8 is at index {1}.", myString, myIndex)
      
      ' Searches for the last occurrence of the duplicated value in a section of the ArrayList.  Note that the start index is greater than the end index because the search is done backward.
      myIndex = myAL.LastIndexOf(myString, 10, 6)
      Console.WriteLine("The last occurrence of ""{0}"" between index 10 and index 5 is at index {1}.", myString, myIndex)
   End Sub
   
   
   Public Shared Sub PrintIndexAndValues(myList As IEnumerable)
      Dim i as Integer
      Dim obj As [Object]
      For Each obj In  myList
         Console.WriteLine("   [{0}]:    {1}", i, obj)
         i = i + 1
      Next obj
      Console.WriteLine()
   End Sub

End Class

' This code produces the following output.
'
' The ArrayList contains the following values:
'    [0]:    the
'    [1]:    quick
'    [2]:    brown
'    [3]:    fox
'    [4]:    jumps
'    [5]:    over
'    [6]:    the
'    [7]:    lazy
'    [8]:    dog
'    [9]:    in
'    [10]:    the
'    [11]:    barn
'
' The last occurrence of "the" is at index 10.
' The last occurrence of "the" between the start and index 8 is at index 6.
' The last occurrence of "the" between index 10 and index 5 is at index 10.

Megjegyzések

A ArrayList rendszer az első elemtől startIndex kezdődően visszafelé keres.

Ez a módszer lineáris keresést végez; ezért ez a módszer egy O(n) művelet, ahol n az elemek száma az elejétől ArrayList aig startIndex.

Ez a metódus hívással határozza meg az egyenlőséget Object.Equals.

Ez a metódus a gyűjtemény objektumait és Equals metódusait CompareToitem használja annak meghatározására, hogy létezik-e elem.

Lásd még

• IndexOf(Object)
• Contains(Object)
• Culture-Insensitive sztringműveletek végrehajtása gyűjteményekben

LastIndexOf(Object, Int32, Int32)

Forrás:

ArrayList.cs

Megkeresi a megadott Object értéket, és visszaadja az utolsó előfordulás nulla alapú indexét azon elemek tartományán belül, amelyek a ArrayList megadott számú elemet tartalmazzák, és a megadott indexben végződnek.

public:
 virtual int LastIndexOf(System::Object ^ value, int startIndex, int count);

public virtual int LastIndexOf(object? value, int startIndex, int count);

abstract member LastIndexOf : obj * int * int -> int
override this.LastIndexOf : obj * int * int -> int

Public Overridable Function LastIndexOf (value As Object, startIndex As Integer, count As Integer) As Integer

Paraméterek

value

Object

A Object keresendő ArrayList. Az érték lehet null.

startIndex

Int32

A visszamenőleges keresés nulla alapú kezdőindexe.

count

Int32

A keresendő szakasz elemeinek száma.

Válaszok

Int32

Az elemek számát tartalmazó value elemek ArrayList tartományán count belüli utolsó előfordulás nullaalapú indexe, ha megtalálható, akkor a vége startIndexpedig -1.

Kivételek

ArgumentOutOfRangeException

startIndexkívül esik az érvényes indexek tartományán.ArrayList

-vagy-

count kisebb, mint nulla.

-vagy-

startIndex és count ne adjon meg érvényes szakaszt a ArrayList.

Példák

Az alábbi példakód bemutatja, hogyan határozható meg egy adott elem utolsó előfordulásának indexe. Vegye figyelembe, hogy LastIndexOf ez egy visszafelé történő keresés, count ezért az értéknek kisebbnek vagy egyenlőnek startIndex kell lennie+ 1-nél.

using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList with three elements of the same value.
      ArrayList myAL = new ArrayList();
      myAL.Add( "the" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumps" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );
      myAL.Add( "in" );
      myAL.Add( "the" );
      myAL.Add( "barn" );

      // Displays the values of the ArrayList.
      Console.WriteLine( "The ArrayList contains the following values:" );
      PrintIndexAndValues( myAL );

      // Searches for the last occurrence of the duplicated value.
      string myString = "the";
      int myIndex = myAL.LastIndexOf( myString );
      Console.WriteLine( "The last occurrence of \"{0}\" is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in the first section of the ArrayList.
      myIndex = myAL.LastIndexOf( myString, 8 );
      Console.WriteLine( "The last occurrence of \"{0}\" between the start and index 8 is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in a section of the ArrayList.  Note that the start index is greater than the end index because the search is done backward.
      myIndex = myAL.LastIndexOf( myString, 10, 6 );
      Console.WriteLine( "The last occurrence of \"{0}\" between index 10 and index 5 is at index {1}.", myString, myIndex );
   }

   public static void PrintIndexAndValues( IEnumerable myList )  {
      int i = 0;
      foreach ( Object obj in myList )
         Console.WriteLine( "   [{0}]:    {1}", i++, obj );
      Console.WriteLine();
   }
}


/*
This code produces the following output.

The ArrayList contains the following values:
   [0]:    the
   [1]:    quick
   [2]:    brown
   [3]:    fox
   [4]:    jumps
   [5]:    over
   [6]:    the
   [7]:    lazy
   [8]:    dog
   [9]:    in
   [10]:    the
   [11]:    barn

The last occurrence of "the" is at index 10.
The last occurrence of "the" between the start and index 8 is at index 6.
The last occurrence of "the" between index 10 and index 5 is at index 10.
*/

Imports System.Collections

Public Class SamplesArrayList
   
   Public Shared Sub Main()
      
      ' Creates and initializes a new ArrayList with three elements of the same value.
      Dim myAL As New ArrayList()
      myAL.Add("the")
      myAL.Add("quick")
      myAL.Add("brown")
      myAL.Add("fox")
      myAL.Add("jumps")
      myAL.Add("over")
      myAL.Add("the")
      myAL.Add("lazy")
      myAL.Add("dog")
      myAL.Add("in")
      myAL.Add("the")
      myAL.Add("barn")
      
      ' Displays the values of the ArrayList.
      Console.WriteLine("The ArrayList contains the following values:")
      PrintIndexAndValues(myAL)
      
      ' Searches for the last occurrence of the duplicated value.
      Dim myString As [String] = "the"
      Dim myIndex As Integer = myAL.LastIndexOf(myString)
      Console.WriteLine("The last occurrence of ""{0}"" is at index {1}.", myString, myIndex)
      
      ' Searches for the last occurrence of the duplicated value in the first section of the ArrayList.
      myIndex = myAL.LastIndexOf(myString, 8)
      Console.WriteLine("The last occurrence of ""{0}"" between the start and index 8 is at index {1}.", myString, myIndex)
      
      ' Searches for the last occurrence of the duplicated value in a section of the ArrayList.  Note that the start index is greater than the end index because the search is done backward.
      myIndex = myAL.LastIndexOf(myString, 10, 6)
      Console.WriteLine("The last occurrence of ""{0}"" between index 10 and index 5 is at index {1}.", myString, myIndex)
   End Sub
   
   
   Public Shared Sub PrintIndexAndValues(myList As IEnumerable)
      Dim i as Integer
      Dim obj As [Object]
      For Each obj In  myList
         Console.WriteLine("   [{0}]:    {1}", i, obj)
         i = i + 1
      Next obj
      Console.WriteLine()
   End Sub

End Class

' This code produces the following output.
'
' The ArrayList contains the following values:
'    [0]:    the
'    [1]:    quick
'    [2]:    brown
'    [3]:    fox
'    [4]:    jumps
'    [5]:    over
'    [6]:    the
'    [7]:    lazy
'    [8]:    dog
'    [9]:    in
'    [10]:    the
'    [11]:    barn
'
' The last occurrence of "the" is at index 10.
' The last occurrence of "the" between the start and index 8 is at index 6.
' The last occurrence of "the" between index 10 and index 5 is at index 10.

Megjegyzések

A ArrayList rendszer visszafelé startIndex keres, és mínusz startIndex plusz 1 értékre count végződik, ha count nagyobb, mint 0.

Ez a módszer lineáris keresést végez; ezért ez a módszer egy O(n) művelet, ahol n van count.

Ez a metódus hívással határozza meg az egyenlőséget Object.Equals.

Ez a metódus a gyűjtemény objektumait és Equals metódusait CompareToitem használja annak meghatározására, hogy létezik-e elem.

Lásd még

• IndexOf(Object)
• Contains(Object)
• Culture-Insensitive sztringműveletek végrehajtása gyűjteményekben