ArrayList.IndexOf Metodo
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Restituisce l'indice in base zero della prima occorrenza di un valore nel ArrayList o in una parte di esso.
Overload
| IndexOf(Object) |
Cerca il Object specificato e restituisce l'indice in base zero della prima occorrenza all'interno dell'intero ArrayList. |
| IndexOf(Object, Int32) |
Cerca il Object specificato e restituisce l'indice in base zero della prima occorrenza all'interno dell'intervallo di elementi nella ArrayList che si estende dall'indice specificato all'ultimo elemento. |
| IndexOf(Object, Int32, Int32) |
Cerca il Object specificato e restituisce l'indice in base zero della prima occorrenza all'interno dell'intervallo di elementi nella ArrayList che inizia in corrispondenza dell'indice specificato e contiene il numero specificato di elementi. |
IndexOf(Object)
- Origine:
- ArrayList.cs
- Origine:
- ArrayList.cs
- Origine:
- ArrayList.cs
public:
virtual int IndexOf(System::Object ^ value);public virtual int IndexOf (object value);public virtual int IndexOf (object? value);abstract member IndexOf : obj -> int
override this.IndexOf : obj -> intPublic Overridable Function IndexOf (value As Object) As IntegerParametri
Restituisce
Indice in base zero della prima occorrenza di value all'interno dell'intero ArrayList, se trovato; in caso contrario, -1.
Implementazioni
Esempio
Nell'esempio di codice seguente viene illustrato come determinare l'indice della prima occorrenza di un elemento specificato.
using namespace System;
using namespace System::Collections;
void PrintIndexAndValues( IEnumerable^ myList );
int main()
{
// Creates and initializes a new ArrayList with three elements of the same value.
ArrayList^ myAL = gcnew 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 );
// Search for the first occurrence of the duplicated value.
String^ myString = "the";
int myIndex = myAL->IndexOf( myString );
Console::WriteLine( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL->IndexOf( myString, 4 );
Console::WriteLine( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL->IndexOf( myString, 6, 6 );
Console::WriteLine( "The first occurrence of \"{0}\" between index 6 and index 11 is at index {1}.", myString, myIndex );
}
void PrintIndexAndValues( IEnumerable^ myList )
{
int i = 0;
IEnumerator^ myEnum = myList->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ obj = safe_cast<Object^>(myEnum->Current);
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 first occurrence of "the" is at index 0.
The first occurrence of "the" between index 4 and the end is at index 6.
The first occurrence of "the" between index 6 and index 11 is at index 6.
*/
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 );
// Search for the first occurrence of the duplicated value.
string myString = "the";
int myIndex = myAL.IndexOf( myString );
Console.WriteLine( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL.IndexOf( myString, 4 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL.IndexOf( myString, 6, 6 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 6 and index 11 is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a small section at the end of the ArrayList.
myIndex = myAL.IndexOf( myString, 11 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 11 and the end 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 output similar to the following:
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 first occurrence of "the" is at index 0.
The first occurrence of "the" between index 4 and the end is at index 6.
The first occurrence of "the" between index 6 and index 11 is at index 6.
The first occurrence of "the" between index 11 and the end is at index -1.
*/
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)
' Search for the first occurrence of the duplicated value.
Dim myString As [String] = "the"
Dim myIndex As Integer = myAL.IndexOf(myString)
Console.WriteLine("The first occurrence of ""{0}"" is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL.IndexOf(myString, 4)
Console.WriteLine("The first occurrence of ""{0}"" between index 4 and the end is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL.IndexOf(myString, 6, 6)
Console.WriteLine("The first occurrence of ""{0}"" between index 6 and index 11 is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in a small section at the end of the ArrayList.
myIndex = myAL.IndexOf(myString, 11)
Console.WriteLine("The first occurrence of ""{0}"" between index 11 and the end is at index {1}.", myString, myIndex)
End Sub
Public Shared Sub PrintIndexAndValues(ByVal 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 first occurrence of "the" is at index 0.
' The first occurrence of "the" between index 4 and the end is at index 6.
' The first occurrence of "the" between index 6 and index 11 is at index 6.
' The first occurrence of "the" between index 11 and the end is at index -1.
'
Commenti
Il ArrayList viene cercato in avanti a partire dal primo elemento e termina con l'ultimo elemento.
Questo metodo esegue una ricerca lineare; pertanto, questo metodo è un'operazione di O(n), in cui n è Count.
Questo metodo determina l'uguaglianza chiamando Object.Equals.
A partire da .NET Framework 2.0, questo metodo usa i metodi Equals e CompareTo degli oggetti della raccolta in item per determinare se l'elemento esiste. Nelle versioni precedenti di .NET Framework questa determinazione è stata effettuata usando i metodi Equals e CompareTo del parametro item sugli oggetti dell'insieme.
Vedi anche
- LastIndexOf(Object)
- Contains(Object)
- esecuzione di operazioni stringa Culture-Insensitive nelle raccolte
Si applica a
IndexOf(Object, Int32)
- Origine:
- ArrayList.cs
- Origine:
- ArrayList.cs
- Origine:
- ArrayList.cs
public:
virtual int IndexOf(System::Object ^ value, int startIndex);public virtual int IndexOf (object value, int startIndex);public virtual int IndexOf (object? value, int startIndex);abstract member IndexOf : obj * int -> int
override this.IndexOf : obj * int -> intPublic Overridable Function IndexOf (value As Object, startIndex As Integer) As IntegerParametri
- startIndex
- Int32
Indice iniziale in base zero della ricerca. 0 (zero) è valido in un elenco vuoto.
Restituisce
Indice in base zero della prima occorrenza di value all'interno dell'intervallo di elementi nel ArrayList che si estende da startIndex all'ultimo elemento, se trovato; in caso contrario, -1.
Eccezioni
startIndex non è compreso nell'intervallo di indici validi per l'ArrayList.
Esempio
Nell'esempio di codice seguente viene illustrato come determinare l'indice della prima occorrenza di un elemento specificato.
using namespace System;
using namespace System::Collections;
void PrintIndexAndValues( IEnumerable^ myList );
int main()
{
// Creates and initializes a new ArrayList with three elements of the same value.
ArrayList^ myAL = gcnew 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 );
// Search for the first occurrence of the duplicated value.
String^ myString = "the";
int myIndex = myAL->IndexOf( myString );
Console::WriteLine( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL->IndexOf( myString, 4 );
Console::WriteLine( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL->IndexOf( myString, 6, 6 );
Console::WriteLine( "The first occurrence of \"{0}\" between index 6 and index 11 is at index {1}.", myString, myIndex );
}
void PrintIndexAndValues( IEnumerable^ myList )
{
int i = 0;
IEnumerator^ myEnum = myList->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ obj = safe_cast<Object^>(myEnum->Current);
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 first occurrence of "the" is at index 0.
The first occurrence of "the" between index 4 and the end is at index 6.
The first occurrence of "the" between index 6 and index 11 is at index 6.
*/
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 );
// Search for the first occurrence of the duplicated value.
string myString = "the";
int myIndex = myAL.IndexOf( myString );
Console.WriteLine( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL.IndexOf( myString, 4 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL.IndexOf( myString, 6, 6 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 6 and index 11 is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a small section at the end of the ArrayList.
myIndex = myAL.IndexOf( myString, 11 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 11 and the end 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 output similar to the following:
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 first occurrence of "the" is at index 0.
The first occurrence of "the" between index 4 and the end is at index 6.
The first occurrence of "the" between index 6 and index 11 is at index 6.
The first occurrence of "the" between index 11 and the end is at index -1.
*/
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)
' Search for the first occurrence of the duplicated value.
Dim myString As [String] = "the"
Dim myIndex As Integer = myAL.IndexOf(myString)
Console.WriteLine("The first occurrence of ""{0}"" is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL.IndexOf(myString, 4)
Console.WriteLine("The first occurrence of ""{0}"" between index 4 and the end is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL.IndexOf(myString, 6, 6)
Console.WriteLine("The first occurrence of ""{0}"" between index 6 and index 11 is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in a small section at the end of the ArrayList.
myIndex = myAL.IndexOf(myString, 11)
Console.WriteLine("The first occurrence of ""{0}"" between index 11 and the end is at index {1}.", myString, myIndex)
End Sub
Public Shared Sub PrintIndexAndValues(ByVal 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 first occurrence of "the" is at index 0.
' The first occurrence of "the" between index 4 and the end is at index 6.
' The first occurrence of "the" between index 6 and index 11 is at index 6.
' The first occurrence of "the" between index 11 and the end is at index -1.
'
Commenti
Il ArrayList viene cercato in avanti a partire da startIndex e termina con l'ultimo elemento.
Questo metodo esegue una ricerca lineare; pertanto, questo metodo è un'operazione di O(n), dove n è il numero di elementi da startIndex alla fine del ArrayList.
Questo metodo determina l'uguaglianza chiamando Object.Equals.
A partire da .NET Framework 2.0, questo metodo usa i metodi Equals e CompareTo degli oggetti della raccolta in item per determinare se l'elemento esiste. Nelle versioni precedenti di .NET Framework questa determinazione è stata effettuata usando i metodi Equals e CompareTo del parametro item sugli oggetti dell'insieme.
Vedi anche
- LastIndexOf(Object)
- Contains(Object)
- esecuzione di operazioni stringa Culture-Insensitive nelle raccolte
Si applica a
IndexOf(Object, Int32, Int32)
- Origine:
- ArrayList.cs
- Origine:
- ArrayList.cs
- Origine:
- ArrayList.cs
public:
virtual int IndexOf(System::Object ^ value, int startIndex, int count);public virtual int IndexOf (object value, int startIndex, int count);public virtual int IndexOf (object? value, int startIndex, int count);abstract member IndexOf : obj * int * int -> int
override this.IndexOf : obj * int * int -> intPublic Overridable Function IndexOf (value As Object, startIndex As Integer, count As Integer) As IntegerParametri
- startIndex
- Int32
Indice iniziale in base zero della ricerca. 0 (zero) è valido in un elenco vuoto.
- count
- Int32
Numero di elementi nella sezione da cercare.
Restituisce
Indice in base zero della prima occorrenza di value all'interno dell'intervallo di elementi nel ArrayList che inizia a startIndex e contiene count numero di elementi, se trovato; in caso contrario, -1.
Eccezioni
startIndex non è compreso nell'intervallo di indici validi per l'ArrayList.
-o-
count è minore di zero.
-o-
startIndex e count non specificano una sezione valida nel ArrayList.
Esempio
Nell'esempio di codice seguente viene illustrato come determinare l'indice della prima occorrenza di un elemento specificato.
using namespace System;
using namespace System::Collections;
void PrintIndexAndValues( IEnumerable^ myList );
int main()
{
// Creates and initializes a new ArrayList with three elements of the same value.
ArrayList^ myAL = gcnew 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 );
// Search for the first occurrence of the duplicated value.
String^ myString = "the";
int myIndex = myAL->IndexOf( myString );
Console::WriteLine( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL->IndexOf( myString, 4 );
Console::WriteLine( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL->IndexOf( myString, 6, 6 );
Console::WriteLine( "The first occurrence of \"{0}\" between index 6 and index 11 is at index {1}.", myString, myIndex );
}
void PrintIndexAndValues( IEnumerable^ myList )
{
int i = 0;
IEnumerator^ myEnum = myList->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ obj = safe_cast<Object^>(myEnum->Current);
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 first occurrence of "the" is at index 0.
The first occurrence of "the" between index 4 and the end is at index 6.
The first occurrence of "the" between index 6 and index 11 is at index 6.
*/
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 );
// Search for the first occurrence of the duplicated value.
string myString = "the";
int myIndex = myAL.IndexOf( myString );
Console.WriteLine( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL.IndexOf( myString, 4 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL.IndexOf( myString, 6, 6 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 6 and index 11 is at index {1}.", myString, myIndex );
// Search for the first occurrence of the duplicated value in a small section at the end of the ArrayList.
myIndex = myAL.IndexOf( myString, 11 );
Console.WriteLine( "The first occurrence of \"{0}\" between index 11 and the end 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 output similar to the following:
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 first occurrence of "the" is at index 0.
The first occurrence of "the" between index 4 and the end is at index 6.
The first occurrence of "the" between index 6 and index 11 is at index 6.
The first occurrence of "the" between index 11 and the end is at index -1.
*/
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)
' Search for the first occurrence of the duplicated value.
Dim myString As [String] = "the"
Dim myIndex As Integer = myAL.IndexOf(myString)
Console.WriteLine("The first occurrence of ""{0}"" is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in the last section of the ArrayList.
myIndex = myAL.IndexOf(myString, 4)
Console.WriteLine("The first occurrence of ""{0}"" between index 4 and the end is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in a section of the ArrayList.
myIndex = myAL.IndexOf(myString, 6, 6)
Console.WriteLine("The first occurrence of ""{0}"" between index 6 and index 11 is at index {1}.", myString, myIndex)
' Search for the first occurrence of the duplicated value in a small section at the end of the ArrayList.
myIndex = myAL.IndexOf(myString, 11)
Console.WriteLine("The first occurrence of ""{0}"" between index 11 and the end is at index {1}.", myString, myIndex)
End Sub
Public Shared Sub PrintIndexAndValues(ByVal 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 first occurrence of "the" is at index 0.
' The first occurrence of "the" between index 4 and the end is at index 6.
' The first occurrence of "the" between index 6 and index 11 is at index 6.
' The first occurrence of "the" between index 11 and the end is at index -1.
'
Commenti
Il ArrayList viene cercato in avanti a partire da startIndex e termina a startIndex più count meno 1, se count è maggiore di 0.
Questo metodo esegue una ricerca lineare; pertanto, questo metodo è un'operazione di O(n), in cui n è count.
Questo metodo determina l'uguaglianza chiamando Object.Equals.
A partire da .NET Framework 2.0, questo metodo usa i metodi Equals e CompareTo degli oggetti della raccolta in item per determinare se l'elemento esiste. Nelle versioni precedenti di .NET Framework questa determinazione è stata effettuata usando i metodi Equals e CompareTo del parametro item sugli oggetti dell'insieme.
Vedi anche
- LastIndexOf(Object)
- Contains(Object)
- esecuzione di operazioni stringa Culture-Insensitive nelle raccolte
Si applica a
Collabora con noi su GitHub
L'origine di questo contenuto è disponibile in GitHub, in cui è anche possibile creare ed esaminare i problemi e le richieste pull. Per ulteriori informazioni, vedere la guida per i collaboratori.
