Array.LastIndexOf Método

  • Referencia

Definición

Espacio de nombres:
System
Ensamblado:
System.Runtime.dll
Ensamblado:
mscorlib.dll
Ensamblado:
netstandard.dll

Devuelve el índice de la última aparición de un valor en una matriz Array unidimensional o en una parte de la matriz Array.

Sobrecargas

LastIndexOf(Array, Object)

Busca el objeto especificado y devuelve el índice de la última aparición en toda la matriz Array unidimensional.
LastIndexOf(Array, Object, Int32)

Busca el objeto especificado y devuelve el índice de la última aparición en el intervalo de elementos de la matriz Array unidimensional que se extiende desde el primer elemento hasta el índice especificado.
LastIndexOf(Array, Object, Int32, Int32)

Busca el objeto especificado y devuelve el índice de la última aparición dentro del intervalo de elementos de la Array unidimensional que contiene el número especificado de elementos y termina en el índice especificado.
LastIndexOf<T>(T[], T)

Busca el objeto especificado y devuelve el índice de la última aparición de toda la Array.
LastIndexOf<T>(T[], T, Int32)

Busca el objeto especificado y devuelve el índice de la última aparición en el intervalo de elementos de la Array que se extiende desde el primer elemento hasta el índice especificado.
LastIndexOf<T>(T[], T, Int32, Int32)

Busca el objeto especificado y devuelve el índice de la última aparición en el intervalo de elementos de la Array que contiene el número de elementos especificado y termina en el índice especificado.

LastIndexOf(Array, Object)

Source:
Array.cs
Source:
Array.cs
Source:
Array.cs

Busca el objeto especificado y devuelve el índice de la última aparición en toda la matriz Array unidimensional.

public:
 static int LastIndexOf(Array ^ array, System::Object ^ value);
public static int LastIndexOf (Array array, object value);
public static int LastIndexOf (Array array, object? value);
static member LastIndexOf : Array * obj -> int
Public Shared Function LastIndexOf (array As Array, value As Object) As Integer

Parámetros

array
Array

Array unidimensional que se va a buscar.

value
Object

Objeto que se va a buscar en array.

Devoluciones

Int32

Índice de la última aparición de value en toda la matriz array, si se encuentra; en caso contrario, límite inferior de la matriz menos 1.

Excepciones

ArgumentNullException

array es null.

RankException

array es multidimensional.

Ejemplos

En el ejemplo de código siguiente se muestra cómo determinar el índice de la última aparición de un elemento especificado en una matriz.

using namespace System;
void PrintIndexAndValues( Array^ myArray );

void main()
{
   // Creates and initializes a new Array instance with three elements of the same value.
   Array^ myArray = Array::CreateInstance( String::typeid, 12 );
   myArray->SetValue( "the", 0 );
   myArray->SetValue( "quick", 1 );
   myArray->SetValue( "brown", 2 );
   myArray->SetValue( "fox", 3 );
   myArray->SetValue( "jumps", 4 );
   myArray->SetValue( "over", 5 );
   myArray->SetValue( "the", 6 );
   myArray->SetValue( "lazy", 7 );
   myArray->SetValue( "dog", 8 );
   myArray->SetValue( "in", 9 );
   myArray->SetValue( "the", 10 );
   myArray->SetValue( "barn", 11 );

   // Displays the values of the Array.
   Console::WriteLine(  "The Array instance contains the following values:" );
   PrintIndexAndValues( myArray );

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

void PrintIndexAndValues( Array^ myArray )
{
   for ( int i = myArray->GetLowerBound( 0 ); i <= myArray->GetUpperBound( 0 ); i++ )
      Console::WriteLine(  "\t[{0}]:\t{1}", i, myArray->GetValue( i ) );
}

/* 
 This code produces the following output.
 
 The Array instance 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 5 and index 10 is at index 10.
 */

let printIndexAndValues (arr: 'a []) =
   for i = arr.GetLowerBound 0 to arr.GetUpperBound 0 do
      printfn $"\t[{i}]:\t{arr[i]}"

// Creates and initializes a new Array with three elements of the same value.
let myArray = 
   [| "the"; "quick"; "brown"; "fox"
      "jumps"; "over"; "the"; "lazy"
      "dog"; "in"; "the"; "barn" |]

// Displays the values of the Array.
printfn "The Array contains the following values:"
printIndexAndValues myArray

// Searches for the last occurrence of the duplicated value.
let myString = "the"
let myIndex = Array.LastIndexOf(myArray, myString)
printfn $"The last occurrence of \"{myString}\" is at index {myIndex}."

// Searches for the last occurrence of the duplicated value in the first section of the Array.
let myIndex = Array.LastIndexOf(myArray, myString, 8)
printfn $"The last occurrence of \"{myString}\" between the start and index 8 is at index {myIndex}."

// Searches for the last occurrence of the duplicated value in a section of the Array.
// Note that the start index is greater than the end index because the search is done backward.
let myIndex = Array.LastIndexOf( myArray, myString, 10, 6 )
printfn $"The last occurrence of \"{myString}\" between index 5 and index 10 is at index {myIndex}."


//      This code produces the following output.
//
//      The Array 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 5 and index 10 is at index 10.

// Creates and initializes a new Array with three elements of the same value.
Array myArray=Array.CreateInstance( typeof(string), 12 );
myArray.SetValue( "the", 0 );
myArray.SetValue( "quick", 1 );
myArray.SetValue( "brown", 2 );
myArray.SetValue( "fox", 3 );
myArray.SetValue( "jumps", 4 );
myArray.SetValue( "over", 5 );
myArray.SetValue( "the", 6 );
myArray.SetValue( "lazy", 7 );
myArray.SetValue( "dog", 8 );
myArray.SetValue( "in", 9 );
myArray.SetValue( "the", 10 );
myArray.SetValue( "barn", 11 );

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

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

void PrintIndexAndValues( Array anArray )  {
   for ( int i = anArray.GetLowerBound(0); i <= anArray.GetUpperBound(0); i++ )
      Console.WriteLine( "\t[{0}]:\t{1}", i, anArray.GetValue( i ) );
}

/*
This code produces the following output.

The Array 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 5 and index 10 is at index 10.
*/

Public Class SamplesArray    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Array with three elements of
        ' the same value.
        Dim myArray As Array = Array.CreateInstance(GetType(String), 12)
        myArray.SetValue("the", 0)
        myArray.SetValue("quick", 1)
        myArray.SetValue("brown", 2)
        myArray.SetValue("fox", 3)
        myArray.SetValue("jumps", 4)
        myArray.SetValue("over", 5)
        myArray.SetValue("the", 6)
        myArray.SetValue("lazy", 7)
        myArray.SetValue("dog", 8)
        myArray.SetValue("in", 9)
        myArray.SetValue("the", 10)
        myArray.SetValue("barn", 11)
        
        ' Displays the values of the Array.
        Console.WriteLine("The Array contains the following values:")
        PrintIndexAndValues(myArray)
        
        ' Searches for the last occurrence of the duplicated value.
        Dim myString As String = "the"
        Dim myIndex As Integer = Array.LastIndexOf(myArray, 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 Array.
        myIndex = Array.LastIndexOf(myArray, 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 Array.  Note that the start index is greater than the end
        ' index because the search is done backward.
        myIndex = Array.LastIndexOf(myArray, myString, 10, 6)
        Console.WriteLine("The last occurrence of ""{0}"" between index 5 " _
           + "and index 10 is at index {1}.", myString, myIndex)
    End Sub
    
    
    Public Shared Sub PrintIndexAndValues(myArray As Array)
        Dim i As Integer
        For i = myArray.GetLowerBound(0) To myArray.GetUpperBound(0)
            Console.WriteLine(ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
               + "{1}", i, myArray.GetValue(i))
        Next i
    End Sub
End Class

' This code produces the following output.
' 
' The Array 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 5 and index 10 is at index 10.

Comentarios

La unidimensional Array se busca hacia atrás a partir del último elemento y finaliza en el primer elemento.

Los elementos se comparan con el valor especificado mediante el Object.Equals método . Si el tipo de elemento es un tipo nointrinsic (definido por el usuario), se usa la Equals implementación de ese tipo.

Dado que la mayoría de las matrices tendrán un límite inferior de cero, este método generalmente devolvería -1 cuando value no se encuentra. En el caso raro de que el límite inferior de la matriz sea igual a Int32.MinValue y value no se encuentre, este método devuelve Int32.MaxValue, que es System.Int32.MinValue - 1.

Este método es una operación O(n), donde n es de Lengtharray.

En .NET Framework 2.0 y versiones posteriores, este método usa los Equals métodos y CompareTo de Array para determinar si Object el especificado por el value parámetro existe. En versiones anteriores de .NET Framework, esta determinación se realizó mediante el uso de los Equals métodos y CompareTo del valueObject propio .

CompareTo métodos del item parámetro en los objetos de la colección.

Consulte también

Se aplica a

LastIndexOf(Array, Object, Int32)

Source:
Array.cs
Source:
Array.cs
Source:
Array.cs

Busca el objeto especificado y devuelve el índice de la última aparición en el intervalo de elementos de la matriz Array unidimensional que se extiende desde el primer elemento hasta el índice especificado.

public:
 static int LastIndexOf(Array ^ array, System::Object ^ value, int startIndex);
public static int LastIndexOf (Array array, object value, int startIndex);
public static int LastIndexOf (Array array, object? value, int startIndex);
static member LastIndexOf : Array * obj * int -> int
Public Shared Function LastIndexOf (array As Array, value As Object, startIndex As Integer) As Integer

Parámetros

array
Array

Array unidimensional que se va a buscar.

value
Object

Objeto que se va a buscar en array.

startIndex
Int32

Índice inicial de la búsqueda hacia atrás.

Devoluciones

Int32

Índice de la última aparición de value en el intervalo de elementos de array que se extiende desde el primer elemento hasta startIndex, si se encuentra; en caso contrario, límite inferior de la matriz menos 1.

Excepciones

ArgumentNullException

array es null.

ArgumentOutOfRangeException

startIndex está fuera del intervalo de índices válidos para la array.

RankException

array es multidimensional.

Ejemplos

En el ejemplo de código siguiente se muestra cómo determinar el índice de la última aparición de un elemento especificado en una matriz.

using namespace System;
void PrintIndexAndValues( Array^ myArray );

void main()
{
   // Creates and initializes a new Array instance with three elements of the same value.
   Array^ myArray = Array::CreateInstance( String::typeid, 12 );
   myArray->SetValue( "the", 0 );
   myArray->SetValue( "quick", 1 );
   myArray->SetValue( "brown", 2 );
   myArray->SetValue( "fox", 3 );
   myArray->SetValue( "jumps", 4 );
   myArray->SetValue( "over", 5 );
   myArray->SetValue( "the", 6 );
   myArray->SetValue( "lazy", 7 );
   myArray->SetValue( "dog", 8 );
   myArray->SetValue( "in", 9 );
   myArray->SetValue( "the", 10 );
   myArray->SetValue( "barn", 11 );

   // Displays the values of the Array.
   Console::WriteLine(  "The Array instance contains the following values:" );
   PrintIndexAndValues( myArray );

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

void PrintIndexAndValues( Array^ myArray )
{
   for ( int i = myArray->GetLowerBound( 0 ); i <= myArray->GetUpperBound( 0 ); i++ )
      Console::WriteLine(  "\t[{0}]:\t{1}", i, myArray->GetValue( i ) );
}

/* 
 This code produces the following output.
 
 The Array instance 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 5 and index 10 is at index 10.
 */

let printIndexAndValues (arr: 'a []) =
   for i = arr.GetLowerBound 0 to arr.GetUpperBound 0 do
      printfn $"\t[{i}]:\t{arr[i]}"

// Creates and initializes a new Array with three elements of the same value.
let myArray = 
   [| "the"; "quick"; "brown"; "fox"
      "jumps"; "over"; "the"; "lazy"
      "dog"; "in"; "the"; "barn" |]

// Displays the values of the Array.
printfn "The Array contains the following values:"
printIndexAndValues myArray

// Searches for the last occurrence of the duplicated value.
let myString = "the"
let myIndex = Array.LastIndexOf(myArray, myString)
printfn $"The last occurrence of \"{myString}\" is at index {myIndex}."

// Searches for the last occurrence of the duplicated value in the first section of the Array.
let myIndex = Array.LastIndexOf(myArray, myString, 8)
printfn $"The last occurrence of \"{myString}\" between the start and index 8 is at index {myIndex}."

// Searches for the last occurrence of the duplicated value in a section of the Array.
// Note that the start index is greater than the end index because the search is done backward.
let myIndex = Array.LastIndexOf( myArray, myString, 10, 6 )
printfn $"The last occurrence of \"{myString}\" between index 5 and index 10 is at index {myIndex}."


//      This code produces the following output.
//
//      The Array 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 5 and index 10 is at index 10.

// Creates and initializes a new Array with three elements of the same value.
Array myArray=Array.CreateInstance( typeof(string), 12 );
myArray.SetValue( "the", 0 );
myArray.SetValue( "quick", 1 );
myArray.SetValue( "brown", 2 );
myArray.SetValue( "fox", 3 );
myArray.SetValue( "jumps", 4 );
myArray.SetValue( "over", 5 );
myArray.SetValue( "the", 6 );
myArray.SetValue( "lazy", 7 );
myArray.SetValue( "dog", 8 );
myArray.SetValue( "in", 9 );
myArray.SetValue( "the", 10 );
myArray.SetValue( "barn", 11 );

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

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

void PrintIndexAndValues( Array anArray )  {
   for ( int i = anArray.GetLowerBound(0); i <= anArray.GetUpperBound(0); i++ )
      Console.WriteLine( "\t[{0}]:\t{1}", i, anArray.GetValue( i ) );
}

/*
This code produces the following output.

The Array 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 5 and index 10 is at index 10.
*/

Public Class SamplesArray    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Array with three elements of
        ' the same value.
        Dim myArray As Array = Array.CreateInstance(GetType(String), 12)
        myArray.SetValue("the", 0)
        myArray.SetValue("quick", 1)
        myArray.SetValue("brown", 2)
        myArray.SetValue("fox", 3)
        myArray.SetValue("jumps", 4)
        myArray.SetValue("over", 5)
        myArray.SetValue("the", 6)
        myArray.SetValue("lazy", 7)
        myArray.SetValue("dog", 8)
        myArray.SetValue("in", 9)
        myArray.SetValue("the", 10)
        myArray.SetValue("barn", 11)
        
        ' Displays the values of the Array.
        Console.WriteLine("The Array contains the following values:")
        PrintIndexAndValues(myArray)
        
        ' Searches for the last occurrence of the duplicated value.
        Dim myString As String = "the"
        Dim myIndex As Integer = Array.LastIndexOf(myArray, 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 Array.
        myIndex = Array.LastIndexOf(myArray, 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 Array.  Note that the start index is greater than the end
        ' index because the search is done backward.
        myIndex = Array.LastIndexOf(myArray, myString, 10, 6)
        Console.WriteLine("The last occurrence of ""{0}"" between index 5 " _
           + "and index 10 is at index {1}.", myString, myIndex)
    End Sub
    
    
    Public Shared Sub PrintIndexAndValues(myArray As Array)
        Dim i As Integer
        For i = myArray.GetLowerBound(0) To myArray.GetUpperBound(0)
            Console.WriteLine(ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
               + "{1}", i, myArray.GetValue(i))
        Next i
    End Sub
End Class

' This code produces the following output.
' 
' The Array 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 5 and index 10 is at index 10.

Comentarios

La unidimensional Array se busca hacia atrás a partir startIndex de y termina en el primer elemento.

Los elementos se comparan con el valor especificado mediante el Object.Equals método . Si el tipo de elemento es un tipo nointrinsic (definido por el usuario), se usa la Equals implementación de ese tipo.

Dado que la mayoría de las matrices tendrán un límite inferior de cero, este método generalmente devolvería -1 cuando value no se encuentra. En el caso raro de que el límite inferior de la matriz sea igual a Int32.MinValue y value no se encuentre, este método devuelve Int32.MaxValue, que es System.Int32.MinValue - 1.

Este método es una operación O(n), donde n es el número de elementos desde el principio de array a startIndex.

En .NET Framework 2.0 y versiones posteriores, este método usa los Equals métodos y CompareTo de Array para determinar si Object el especificado por el value parámetro existe. En versiones anteriores de .NET Framework, esta determinación se realizó mediante el uso de los Equals métodos y CompareTo del valueObject propio .

Consulte también

Se aplica a

LastIndexOf(Array, Object, Int32, Int32)

Source:
Array.cs
Source:
Array.cs
Source:
Array.cs

Busca el objeto especificado y devuelve el índice de la última aparición dentro del intervalo de elementos de la Array unidimensional que contiene el número especificado de elementos y termina en el índice especificado.

public:
 static int LastIndexOf(Array ^ array, System::Object ^ value, int startIndex, int count);
public static int LastIndexOf (Array array, object value, int startIndex, int count);
public static int LastIndexOf (Array array, object? value, int startIndex, int count);
static member LastIndexOf : Array * obj * int * int -> int
Public Shared Function LastIndexOf (array As Array, value As Object, startIndex As Integer, count As Integer) As Integer

Parámetros

array
Array

Array unidimensional que se va a buscar.

value
Object

Objeto que se va a buscar en array.

startIndex
Int32

Índice inicial de la búsqueda hacia atrás.

count
Int32

Número de elementos de la sección en la que se va a realizar la búsqueda.

Devoluciones

Int32

El índice de la última aparición de value dentro del intervalo de elementos de array que contiene el número de elementos especificado en count y termina en startIndex, si se encuentra; en caso contrario, el límite inferior de la matriz menos 1.

Excepciones

ArgumentNullException

array es null.

ArgumentOutOfRangeException

startIndex está fuera del intervalo de índices válidos para la array.

o bien

count es menor que cero.

o bien

startIndex y count no especifican una sección válida en array.

RankException

array es multidimensional.

Ejemplos

En el ejemplo de código siguiente se muestra cómo determinar el índice de la última aparición de un elemento especificado en una matriz. Tenga en cuenta que el LastIndexOf método es una búsqueda hacia atrás; por lo tanto, count debe ser menor o igual que (startIndex menos el límite inferior de la matriz más 1).

using namespace System;
void PrintIndexAndValues( Array^ myArray );

void main()
{
   // Creates and initializes a new Array instance with three elements of the same value.
   Array^ myArray = Array::CreateInstance( String::typeid, 12 );
   myArray->SetValue( "the", 0 );
   myArray->SetValue( "quick", 1 );
   myArray->SetValue( "brown", 2 );
   myArray->SetValue( "fox", 3 );
   myArray->SetValue( "jumps", 4 );
   myArray->SetValue( "over", 5 );
   myArray->SetValue( "the", 6 );
   myArray->SetValue( "lazy", 7 );
   myArray->SetValue( "dog", 8 );
   myArray->SetValue( "in", 9 );
   myArray->SetValue( "the", 10 );
   myArray->SetValue( "barn", 11 );

   // Displays the values of the Array.
   Console::WriteLine(  "The Array instance contains the following values:" );
   PrintIndexAndValues( myArray );

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

void PrintIndexAndValues( Array^ myArray )
{
   for ( int i = myArray->GetLowerBound( 0 ); i <= myArray->GetUpperBound( 0 ); i++ )
      Console::WriteLine(  "\t[{0}]:\t{1}", i, myArray->GetValue( i ) );
}

/* 
 This code produces the following output.
 
 The Array instance 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 5 and index 10 is at index 10.
 */

let printIndexAndValues (arr: 'a []) =
   for i = arr.GetLowerBound 0 to arr.GetUpperBound 0 do
      printfn $"\t[{i}]:\t{arr[i]}"

// Creates and initializes a new Array with three elements of the same value.
let myArray = 
   [| "the"; "quick"; "brown"; "fox"
      "jumps"; "over"; "the"; "lazy"
      "dog"; "in"; "the"; "barn" |]

// Displays the values of the Array.
printfn "The Array contains the following values:"
printIndexAndValues myArray

// Searches for the last occurrence of the duplicated value.
let myString = "the"
let myIndex = Array.LastIndexOf(myArray, myString)
printfn $"The last occurrence of \"{myString}\" is at index {myIndex}."

// Searches for the last occurrence of the duplicated value in the first section of the Array.
let myIndex = Array.LastIndexOf(myArray, myString, 8)
printfn $"The last occurrence of \"{myString}\" between the start and index 8 is at index {myIndex}."

// Searches for the last occurrence of the duplicated value in a section of the Array.
// Note that the start index is greater than the end index because the search is done backward.
let myIndex = Array.LastIndexOf( myArray, myString, 10, 6 )
printfn $"The last occurrence of \"{myString}\" between index 5 and index 10 is at index {myIndex}."


//      This code produces the following output.
//
//      The Array 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 5 and index 10 is at index 10.

// Creates and initializes a new Array with three elements of the same value.
Array myArray=Array.CreateInstance( typeof(string), 12 );
myArray.SetValue( "the", 0 );
myArray.SetValue( "quick", 1 );
myArray.SetValue( "brown", 2 );
myArray.SetValue( "fox", 3 );
myArray.SetValue( "jumps", 4 );
myArray.SetValue( "over", 5 );
myArray.SetValue( "the", 6 );
myArray.SetValue( "lazy", 7 );
myArray.SetValue( "dog", 8 );
myArray.SetValue( "in", 9 );
myArray.SetValue( "the", 10 );
myArray.SetValue( "barn", 11 );

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

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

void PrintIndexAndValues( Array anArray )  {
   for ( int i = anArray.GetLowerBound(0); i <= anArray.GetUpperBound(0); i++ )
      Console.WriteLine( "\t[{0}]:\t{1}", i, anArray.GetValue( i ) );
}

/*
This code produces the following output.

The Array 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 5 and index 10 is at index 10.
*/

Public Class SamplesArray    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Array with three elements of
        ' the same value.
        Dim myArray As Array = Array.CreateInstance(GetType(String), 12)
        myArray.SetValue("the", 0)
        myArray.SetValue("quick", 1)
        myArray.SetValue("brown", 2)
        myArray.SetValue("fox", 3)
        myArray.SetValue("jumps", 4)
        myArray.SetValue("over", 5)
        myArray.SetValue("the", 6)
        myArray.SetValue("lazy", 7)
        myArray.SetValue("dog", 8)
        myArray.SetValue("in", 9)
        myArray.SetValue("the", 10)
        myArray.SetValue("barn", 11)
        
        ' Displays the values of the Array.
        Console.WriteLine("The Array contains the following values:")
        PrintIndexAndValues(myArray)
        
        ' Searches for the last occurrence of the duplicated value.
        Dim myString As String = "the"
        Dim myIndex As Integer = Array.LastIndexOf(myArray, 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 Array.
        myIndex = Array.LastIndexOf(myArray, 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 Array.  Note that the start index is greater than the end
        ' index because the search is done backward.
        myIndex = Array.LastIndexOf(myArray, myString, 10, 6)
        Console.WriteLine("The last occurrence of ""{0}"" between index 5 " _
           + "and index 10 is at index {1}.", myString, myIndex)
    End Sub
    
    
    Public Shared Sub PrintIndexAndValues(myArray As Array)
        Dim i As Integer
        For i = myArray.GetLowerBound(0) To myArray.GetUpperBound(0)
            Console.WriteLine(ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
               + "{1}", i, myArray.GetValue(i))
        Next i
    End Sub
End Class

' This code produces the following output.
' 
' The Array 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 5 and index 10 is at index 10.

Comentarios

La unidimensional Array se busca hacia atrás a startIndex partir de y termina en startIndex menos count 1, si count es mayor que 0.

Los elementos se comparan con el valor especificado mediante el Object.Equals método . Si el tipo de elemento es un tipo nointrinsic (definido por el usuario), se usa laEquals implementación de ese tipo.

Dado que la mayoría de las matrices tendrán un límite inferior de cero, este método generalmente devolvería -1 cuando value no se encuentra. En el caso raro de que el límite inferior de la matriz sea igual a Int32.MinValue y value no se encuentre, este método devuelve Int32.MaxValue, que es System.Int32.MinValue - 1.

Este método es una operación O(n), donde n es count.

En .NET Framework 2.0 y versiones posteriores, este método usa los Equals métodos y CompareTo de Array para determinar si Object el especificado por el value parámetro existe. En versiones anteriores de .NET Framework, esta determinación se realizó mediante el uso de los Equals métodos y CompareTo del valueObject propio .

Consulte también

Se aplica a

LastIndexOf<T>(T[], T)

Source:
Array.cs
Source:
Array.cs
Source:
Array.cs

Busca el objeto especificado y devuelve el índice de la última aparición de toda la Array.

public:
generic <typename T>
 static int LastIndexOf(cli::array <T> ^ array, T value);
public static int LastIndexOf<T> (T[] array, T value);
static member LastIndexOf : 'T[] * 'T -> int
Public Shared Function LastIndexOf(Of T) (array As T(), value As T) As Integer

Parámetros de tipo

T

Tipo de los elementos de la matriz.

Parámetros

array
T[]

Array unidimensional de base cero en la que se realizará la búsqueda.

value
T

Objeto que se va a buscar en array.

Devoluciones

Int32

Índice de base cero de la última aparición de value en toda la array, si se encuentra; en caso contrario, -1.

Excepciones

ArgumentNullException

array es null.

Ejemplos

En el ejemplo de código siguiente se muestran las tres sobrecargas genéricas del LastIndexOf método . Se crea una matriz de cadenas, con una entrada que aparece dos veces, en la ubicación del índice 0 y la ubicación del índice 5. La LastIndexOf<T>(T[], T) sobrecarga del método busca en toda la matriz desde el final y busca la segunda aparición de la cadena. La LastIndexOf<T>(T[], T, Int32) sobrecarga del método se usa para buscar la matriz hacia atrás a partir de la ubicación de índice 3 y continuar hasta el principio de la matriz, y busca la primera aparición de la cadena. Por último, la LastIndexOf<T>(T[], T, Int32, Int32) sobrecarga del método se usa para buscar en un intervalo de cuatro entradas, empezando por la ubicación del índice 4 y extendiendo hacia atrás (es decir, busca los elementos en las ubicaciones 4, 3, 2 y 1); esta búsqueda devuelve -1 porque no hay instancias de la cadena de búsqueda en ese intervalo.

using namespace System;

void main()
{
    array<String^>^ dinosaurs = { "Tyrannosaurus", 
        "Amargasaurus",
        "Mamenchisaurus",
        "Brachiosaurus",
        "Deinonychus",
        "Tyrannosaurus",
        "Compsognathus" };

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

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

    Console::WriteLine(
        "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}", 
        Array::LastIndexOf(dinosaurs, "Tyrannosaurus", 3));

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

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1
 */

string[] dinosaurs = { "Tyrannosaurus",
    "Amargasaurus",
    "Mamenchisaurus",
    "Brachiosaurus",
    "Deinonychus",
    "Tyrannosaurus",
    "Compsognathus" };

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

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

Console.WriteLine(
    "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}",
    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3));

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

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1
*/

open System

let dinosaurs = 
    [| "Tyrannosaurus"
       "Amargasaurus"
       "Mamenchisaurus"
       "Brachiosaurus"
       "Deinonychus"
       "Tyrannosaurus"
       "Compsognathus" |]

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

Array.LastIndexOf(dinosaurs, "Tyrannosaurus")
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\"): %i"

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3)
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): %i"

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4)
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 4, 4): %i"

// This code example produces the following output:
//    
//    Tyrannosaurus
//    Amargasaurus
//    Mamenchisaurus
//    Brachiosaurus
//    Deinonychus
//    Tyrannosaurus
//    Compsognathus
//    
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5
//
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0
//
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { "Tyrannosaurus", _
            "Amargasaurus", _
            "Mamenchisaurus", _
            "Brachiosaurus", _
            "Deinonychus", _
            "Tyrannosaurus", _
            "Compsognathus" }

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

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus""): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus"))

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus"", 3): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3))

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus"", 4, 4): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4))

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Deinonychus
'Tyrannosaurus
'Compsognathus
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1

Comentarios

Array se busca hacia atrás a partir del último elemento y finaliza en el primer elemento.

Los elementos se comparan con el valor especificado mediante el Object.Equals método . Si el tipo de elemento es un tipo nointrinsic (definido por el usuario), se usa la Equals implementación de ese tipo.

Este método es una operación O(n), donde n es de Lengtharray.

Consulte también

Se aplica a

LastIndexOf<T>(T[], T, Int32)

Source:
Array.cs
Source:
Array.cs
Source:
Array.cs

Busca el objeto especificado y devuelve el índice de la última aparición en el intervalo de elementos de la Array que se extiende desde el primer elemento hasta el índice especificado.

public:
generic <typename T>
 static int LastIndexOf(cli::array <T> ^ array, T value, int startIndex);
public static int LastIndexOf<T> (T[] array, T value, int startIndex);
static member LastIndexOf : 'T[] * 'T * int -> int
Public Shared Function LastIndexOf(Of T) (array As T(), value As T, startIndex As Integer) As Integer

Parámetros de tipo

T

Tipo de los elementos de la matriz.

Parámetros

array
T[]

Array unidimensional de base cero en la que se realizará la búsqueda.

value
T

Objeto que se va a buscar en array.

startIndex
Int32

Índice inicial de base cero de la búsqueda hacia atrás.

Devoluciones

Int32

Índice de base cero de la última aparición de value dentro del intervalo de elementos de array que abarca desde el primer elemento hasta startIndex, si se encuentra; de lo contrario, -1.

Excepciones

ArgumentNullException

array es null.

ArgumentOutOfRangeException

startIndex está fuera del intervalo de índices válidos para la array.

Ejemplos

En el ejemplo de código siguiente se muestran las tres sobrecargas genéricas del LastIndexOf método . Se crea una matriz de cadenas, con una entrada que aparece dos veces, en la ubicación del índice 0 y la ubicación del índice 5. La LastIndexOf<T>(T[], T) sobrecarga del método busca en toda la matriz desde el final y busca la segunda aparición de la cadena. La LastIndexOf<T>(T[], T, Int32) sobrecarga del método se usa para buscar la matriz hacia atrás a partir de la ubicación de índice 3 y continuar hasta el principio de la matriz, y busca la primera aparición de la cadena. Por último, la LastIndexOf<T>(T[], T, Int32, Int32) sobrecarga del método se usa para buscar en un intervalo de cuatro entradas, empezando por la ubicación del índice 4 y extendiendo hacia atrás (es decir, busca los elementos en las ubicaciones 4, 3, 2 y 1); esta búsqueda devuelve -1 porque no hay instancias de la cadena de búsqueda en ese intervalo.

using namespace System;

void main()
{
    array<String^>^ dinosaurs = { "Tyrannosaurus", 
        "Amargasaurus",
        "Mamenchisaurus",
        "Brachiosaurus",
        "Deinonychus",
        "Tyrannosaurus",
        "Compsognathus" };

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

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

    Console::WriteLine(
        "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}", 
        Array::LastIndexOf(dinosaurs, "Tyrannosaurus", 3));

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

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1
 */

string[] dinosaurs = { "Tyrannosaurus",
    "Amargasaurus",
    "Mamenchisaurus",
    "Brachiosaurus",
    "Deinonychus",
    "Tyrannosaurus",
    "Compsognathus" };

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

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

Console.WriteLine(
    "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}",
    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3));

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

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1
*/

open System

let dinosaurs = 
    [| "Tyrannosaurus"
       "Amargasaurus"
       "Mamenchisaurus"
       "Brachiosaurus"
       "Deinonychus"
       "Tyrannosaurus"
       "Compsognathus" |]

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

Array.LastIndexOf(dinosaurs, "Tyrannosaurus")
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\"): %i"

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3)
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): %i"

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4)
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 4, 4): %i"

// This code example produces the following output:
//    
//    Tyrannosaurus
//    Amargasaurus
//    Mamenchisaurus
//    Brachiosaurus
//    Deinonychus
//    Tyrannosaurus
//    Compsognathus
//    
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5
//
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0
//
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { "Tyrannosaurus", _
            "Amargasaurus", _
            "Mamenchisaurus", _
            "Brachiosaurus", _
            "Deinonychus", _
            "Tyrannosaurus", _
            "Compsognathus" }

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

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus""): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus"))

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus"", 3): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3))

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus"", 4, 4): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4))

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Deinonychus
'Tyrannosaurus
'Compsognathus
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1

Comentarios

Array Se busca hacia atrás empezando por startIndex y finalizando en el primer elemento.

Los elementos se comparan con el valor especificado mediante el Object.Equals método . Si el tipo de elemento es un tipo nointrinsic (definido por el usuario), se usa la Equals implementación de ese tipo.

Este método es una operación O(n), donde n es el número de elementos desde el principio de array a startIndex.

Consulte también

Se aplica a

LastIndexOf<T>(T[], T, Int32, Int32)

Source:
Array.cs
Source:
Array.cs
Source:
Array.cs

Busca el objeto especificado y devuelve el índice de la última aparición en el intervalo de elementos de la Array que contiene el número de elementos especificado y termina en el índice especificado.

public:
generic <typename T>
 static int LastIndexOf(cli::array <T> ^ array, T value, int startIndex, int count);
public static int LastIndexOf<T> (T[] array, T value, int startIndex, int count);
static member LastIndexOf : 'T[] * 'T * int * int -> int
Public Shared Function LastIndexOf(Of T) (array As T(), value As T, startIndex As Integer, count As Integer) As Integer

Parámetros de tipo

T

Tipo de los elementos de la matriz.

Parámetros

array
T[]

Array unidimensional de base cero en la que se realizará la búsqueda.

value
T

Objeto que se va a buscar en array.

startIndex
Int32

Índice inicial de base cero de la búsqueda hacia atrás.

count
Int32

Número de elementos de la sección en la que se va a realizar la búsqueda.

Devoluciones

Int32

Índice de base cero de la última aparición de value dentro del intervalo de elementos de array que contiene el número de elementos especificado en count y termina en startIndex, si se encuentra; de lo contrario, -1.

Excepciones

ArgumentNullException

array es null.

ArgumentOutOfRangeException

startIndex está fuera del intervalo de índices válidos para la array.

o bien

count es menor que cero.

o bien

startIndex y count no especifican una sección válida en array.

Ejemplos

En el ejemplo de código siguiente se muestran las tres sobrecargas genéricas del LastIndexOf método . Se crea una matriz de cadenas, con una entrada que aparece dos veces, en la ubicación del índice 0 y la ubicación del índice 5. La LastIndexOf<T>(T[], T) sobrecarga del método busca toda la matriz desde el final y busca la segunda aparición de la cadena. La LastIndexOf<T>(T[], T, Int32) sobrecarga del método se usa para buscar la matriz hacia atrás a partir de la ubicación del índice 3 y continuar hasta el principio de la matriz y busca la primera aparición de la cadena. Por último, la sobrecarga del LastIndexOf<T>(T[], T, Int32, Int32) método se usa para buscar en un intervalo de cuatro entradas, empezando por la ubicación del índice 4 y extendiéndose hacia atrás (es decir, busca los elementos en las ubicaciones 4, 3, 2 y 1); esta búsqueda devuelve -1 porque no hay ninguna instancia de la cadena de búsqueda en ese intervalo.

using namespace System;

void main()
{
    array<String^>^ dinosaurs = { "Tyrannosaurus", 
        "Amargasaurus",
        "Mamenchisaurus",
        "Brachiosaurus",
        "Deinonychus",
        "Tyrannosaurus",
        "Compsognathus" };

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

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

    Console::WriteLine(
        "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}", 
        Array::LastIndexOf(dinosaurs, "Tyrannosaurus", 3));

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

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1
 */

string[] dinosaurs = { "Tyrannosaurus",
    "Amargasaurus",
    "Mamenchisaurus",
    "Brachiosaurus",
    "Deinonychus",
    "Tyrannosaurus",
    "Compsognathus" };

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

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

Console.WriteLine(
    "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): {0}",
    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3));

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

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1
*/

open System

let dinosaurs = 
    [| "Tyrannosaurus"
       "Amargasaurus"
       "Mamenchisaurus"
       "Brachiosaurus"
       "Deinonychus"
       "Tyrannosaurus"
       "Compsognathus" |]

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

Array.LastIndexOf(dinosaurs, "Tyrannosaurus")
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\"): %i"

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3)
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 3): %i"

Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4)
|> printfn "\nArray.LastIndexOf(dinosaurs, \"Tyrannosaurus\", 4, 4): %i"

// This code example produces the following output:
//    
//    Tyrannosaurus
//    Amargasaurus
//    Mamenchisaurus
//    Brachiosaurus
//    Deinonychus
//    Tyrannosaurus
//    Compsognathus
//    
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5
//
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0
//
//    Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { "Tyrannosaurus", _
            "Amargasaurus", _
            "Mamenchisaurus", _
            "Brachiosaurus", _
            "Deinonychus", _
            "Tyrannosaurus", _
            "Compsognathus" }

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

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus""): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus"))

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus"", 3): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3))

        Console.WriteLine(vbLf & _
            "Array.LastIndexOf(dinosaurs, ""Tyrannosaurus"", 4, 4): {0}", _
            Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4))

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Deinonychus
'Tyrannosaurus
'Compsognathus
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus"): 5
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 3): 0
'
'Array.LastIndexOf(dinosaurs, "Tyrannosaurus", 4, 4): -1

Comentarios

Array Se busca hacia atrás empezando por startIndex y finalizando en startIndex menos count más 1, si count es mayor que 0.

Los elementos se comparan con el valor especificado mediante el Object.Equals método . Si el tipo de elemento es un tipo nointrinsic (definido por el usuario), se usa la Equals implementación de ese tipo.

Este método es una operación O(n), donde n es count.

Consulte también

Se aplica a