Array.Clear Metoda

Definice

Obor názvů:

System

Sestavení:

netstandard.dll, System.Runtime.dll

Přetížení

Name	Description
Clear(Array)	Vymaže obsah pole.
Clear(Array, Int32, Int32)	Nastaví rozsah prvků v poli na výchozí hodnotu každého typu prvku.

Clear(Array)

Zdroj:

Array.cs

Vymaže obsah pole.

public:
 static void Clear(Array ^ array);

public static void Clear(Array array);

static member Clear : Array -> unit

Public Shared Sub Clear (array As Array)

Parametry

array

Array

Pole, které chcete vymazat.

Výjimky

ArgumentNullException

array je null.

Clear(Array, Int32, Int32)

Zdroj:

Array.cs

Nastaví rozsah prvků v poli na výchozí hodnotu každého typu prvku.

public:
 static void Clear(Array ^ array, int index, int length);

public static void Clear(Array array, int index, int length);

static member Clear : Array * int * int -> unit

Public Shared Sub Clear (array As Array, index As Integer, length As Integer)

Parametry

array

Array

Pole, jehož prvky je třeba vymazat.

index

Int32

Počáteční index rozsahu prvků, které se mají vymazat.

length

Int32

Počet prvků, které se mají vymazat.

Výjimky

ArgumentNullException

array je null.

IndexOutOfRangeException

index je menší než dolní mez array.

nebo

Hodnota length je menší než nula.

nebo

Součet index a length je větší než velikost array.

Příklady

Následující příklad používá metodu Clear k resetování celočíselné hodnoty v jednorozměrném, dvojrozměrném a trojrozměrném poli.

using System;

class Example
{
    public static void RunIt()
    {
        Console.WriteLine("One dimension (Rank=1):");
        int[] numbers1 = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

        for (int i = 0; i < 9; i++)
        {
            Console.Write("{0} ", numbers1[i]);
        }
        Console.WriteLine();
        Console.WriteLine();

        Console.WriteLine("Array.Clear(numbers1, 2, 5)");
        Array.Clear(numbers1, 2, 5);

        for (int i = 0; i < 9; i++)
        {
            Console.Write("{0} ", numbers1[i]);
        }
        Console.WriteLine();
        Console.WriteLine();

        Console.WriteLine("Two dimensions (Rank=2):");
        int[,] numbers2 = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };

        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 3; j++)
            {
                Console.Write("{0} ", numbers2[i, j]);
            }
            Console.WriteLine();
        }

        Console.WriteLine();
        Console.WriteLine("Array.Clear(numbers2, 2, 5)");
        Array.Clear(numbers2, 2, 5);

        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 3; j++)
            {
                Console.Write("{0} ", numbers2[i, j]);
            }
            Console.WriteLine();
        }

        Console.WriteLine("\nThree dimensions (Rank=3):");
        int[,,] numbers3 = {{{1, 2}, {3, 4}},
                             {{5, 6}, {7, 8}},
                             {{9, 10}, {11, 12}}};

        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 2; j++)
            {
                for (int k = 0; k < 2; k++)
                {
                    Console.Write("{0} ", numbers3[i, j, k]);
                }
                Console.WriteLine();
            }
            Console.WriteLine();
        }

        Console.WriteLine("Array.Clear(numbers3, 2, 5)");
        Array.Clear(numbers3, 2, 5);

        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 2; j++)
            {
                for (int k = 0; k < 2; k++)
                {
                    Console.Write("{0} ", numbers3[i, j, k]);
                }
                Console.WriteLine();
            }
            Console.WriteLine();
        }
    }
}

/*  This code example produces the following output:
 *
 * One dimension (Rank=1):
 * 1 2 3 4 5 6 7 8 9
 *
 * Array.Clear(numbers1, 2, 5)
 * 1 2 0 0 0 0 0 8 9
 *
 * Two dimensions (Rank=2):
 * 1 2 3
 * 4 5 6
 * 7 8 9
 *
 * Array.Clear(numbers2, 2, 5)
 * 1 2 0
 * 0 0 0
 * 0 8 9
 *
 * Three dimensions (Rank=3):
 * 1 2
 * 3 4
 * 
 * 5 6
 * 7 8
 * 
 * 9 10
 * 11 12
 * 
 * Array.Clear(numbers3, 2, 5)
 * 1 2
 * 0 0
 * 
 * 0 0
 * 0 8
 * 
 * 9 10
 * 11 12
 */

open System

printfn "One dimension (Rank=1):"
let numbers1 = [| 1..9 |]

for i in numbers1 do
    printf $"{i} "
printfn "\n\nArray.Clear(numbers1, 2, 5)"

Array.Clear(numbers1, 2, 5)

for i in numbers1 do
    printf $"{i} "

printfn "\n\nTwo dimensions (Rank=2):"

let numbers2 = array2D [ [ 1; 2; 3 ]; [ 4; 5; 6 ]; [ 7; 8; 9 ] ]

for i = 0 to 2 do
    for j = 0 to 2 do
        printfn $"{numbers2[i, j]} "
    printfn ""

printfn "\nArray.Clear(numbers2, 2, 5)"
Array.Clear(numbers2, 2, 5)

for i = 0 to 2 do
    for j = 0 to 2 do
        printfn $"{numbers2[i, j]} "
    printfn ""

printfn "Three dimensions (Rank=3):"
let numbers3 = Array3D.zeroCreate 2 2 2
numbers3[0, 0, 0] <- 1
numbers3[0, 0, 1] <- 2
numbers3[0, 1, 0] <- 3
numbers3[0, 1, 1] <- 4
numbers3[1, 0, 0] <- 5
numbers3[1, 1, 0] <- 7
numbers3[1, 0, 1] <- 6
numbers3[1, 1, 1] <- 8
numbers3[2, 0, 0] <- 9
numbers3[2, 1, 0] <- 10
numbers3[2, 0, 1] <- 11
numbers3[2, 1, 1] <- 12

for i = 0 to 2 do
    for j = 0 to 1 do
        for k = 0 to 1 do
            printf $"{numbers3[i, j, k]} "
        printfn ""
    printfn ""

printfn "Array.Clear(numbers3, 2, 5)"
Array.Clear(numbers3, 2, 5)

for i = 0 to 1 do
    for j = 0 to 1 do
        for k = 0 to 1 do
            printf $"{numbers3[i, j, k]} "
        printfn ""
    printfn ""

//  This code example produces the following output:
//
// One dimension (Rank=1):
// 1 2 3 4 5 6 7 8 9
//
// Array.Clear(numbers1, 2, 5)
// 1 2 0 0 0 0 0 8 9
//
// Two dimensions (Rank=2):
// 1 2 3
// 4 5 6
// 7 8 9
//
// Array.Clear(numbers2, 2, 5)
// 1 2 0
// 0 0 0
// 0 8 9
//
// Three dimensions (Rank=3):
// 1 2
// 3 4
//
// 5 6
// 7 8
//
// 9 10
// 11 12
//
// Array.Clear(numbers3, 2, 5)
// 1 2
// 0 0
//
// 0 0
// 0 8
//
// 9 10
// 11 12
//

Module Example
    Sub RunIt()
        Console.WriteLine(vbLf & "One dimension (Rank=1):")
        Dim numbers1() As Integer = {1, 2, 3, 4, 5, 6, 7, 8, 9}

        For i As Integer = 0 To 8
            Console.Write("{0} ", numbers1(i))
        Next
        Console.WriteLine()

        Console.WriteLine(vbLf & "Array.Clear(numbers1, 2, 5)")
        Array.Clear(numbers1, 2, 5)

        For i As Integer = 0 To 8
            Console.Write("{0} ", numbers1(i))
        Next
        Console.WriteLine()


        Console.WriteLine(vbLf & "Two dimensions (Rank=2):")
        Dim numbers2(,) As Integer = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}

        For i As Integer = 0 To 2
            For j As Integer = 0 To 2
                Console.Write("{0} ", numbers2(i, j))
            Next
            Console.WriteLine()
        Next

        Console.WriteLine(vbLf & "Array.Clear(numbers2, 2, 5)")
        Array.Clear(numbers2, 2, 5)

        For i As Integer = 0 To 2
            For j As Integer = 0 To 2
                Console.Write("{0} ", numbers2(i, j))
            Next
            Console.WriteLine()
        Next

        Console.WriteLine(vbLf & "Three dimensions (Rank=3):")
        Dim numbers3(,,) As Integer = {{{1, 2}, {3, 4}},
                                       {{5, 6}, {7, 8}},
                                       {{9, 10}, {11, 12}}}

        For i As Integer = 0 To 2
            For j As Integer = 0 To 1
                For k As Integer = 0 To 1
                    Console.Write("{0} ", numbers3(i, j, k))
                Next
                Console.WriteLine()
            Next
            Console.WriteLine()
        Next

        Console.WriteLine("Array.Clear(numbers3, 2, 5)")
        Array.Clear(numbers3, 2, 5)

        For i As Integer = 0 To 2
            For j As Integer = 0 To 1
                For k As Integer = 0 To 1
                    Console.Write("{0} ", numbers3(i, j, k))
                Next
                Console.WriteLine()
            Next
            Console.WriteLine()
        Next
    End Sub
End Module

' The example displays the following output:
'       One dimension (Rank=1):
'       1 2 3 4 5 6 7 8 9
'
'       Array.Clear(numbers1, 2, 5)
'       1 2 0 0 0 0 0 8 9
'
'       Two dimensions (Rank=2):
'       1 2 3
'       4 5 6
'       7 8 9
'
'       Array.Clear(numbers2, 2, 5)
'       1 2 0
'       0 0 0
'       0 8 9
'
'       Three dimensions (Rank=3):
'       1 2
'       3 4
'       
'       5 6
'       7 8
'       
'       9 10
'       11 12
'       
'       Array.Clear(numbers3, 2, 5)
'       1 2
'       0 0
'       
'       0 0
'       0 8
'       
'       9 10
'       11 12

Následující příklad definuje TimeZoneTime strukturu, která obsahuje TimeZoneInfo pole a DateTimeOffset pole. Potom volá metodu Clear , která vymaže jeden prvek v poli dvou elementů TimeZoneTime hodnot. Metoda nastaví hodnotu vymazání elementu na výchozí hodnotu TimeZoneInfo objektu, což je null, a výchozí hodnota objektu DateTimeOffset , což je DateTimeOffset.MinValue.

using System;

public struct TimeZoneTime
{
    public TimeZoneTime(DateTimeOffset dateTime, TimeZoneInfo timeZone)
    {
        DateTime = dateTime;
        TimeZone = timeZone;
    }

    public DateTimeOffset DateTime { get; }

    public TimeZoneInfo TimeZone { get; }
}

public class Example1
{
    public static void RunIt()
    {
        // Declare an array with two elements.
        TimeZoneTime[] timeZoneTimes = {
            new(DateTime.Now, TimeZoneInfo.Local),
            new(DateTime.Now, TimeZoneInfo.Utc)
        };
        foreach (var timeZoneTime in timeZoneTimes)
            Console.WriteLine("{0}: {1:G}",
                              timeZoneTime.TimeZone == null ? "<null>" : timeZoneTime.TimeZone.ToString(),
                              timeZoneTime.DateTime);
        Console.WriteLine();

        Array.Clear(timeZoneTimes, 1, 1);
        foreach (var timeZoneTime in timeZoneTimes)
            Console.WriteLine("{0}: {1:G}",
                              timeZoneTime.TimeZone == null ? "<null>" : timeZoneTime.TimeZone.ToString(),
                              timeZoneTime.DateTime);
    }
}

// The example displays the following output:
//       (UTC-08:00) Pacific Time (US & Canada): 1/20/2014 12:11:00 PM
//       UTC: 1/20/2014 12:11:00 PM
//
//       (UTC-08:00) Pacific Time (US & Canada): 1/20/2014 12:11:00 PM
//       <null>: 1/1/0001 12:00:00 AM

open System

[<Struct>]
type TimeZoneTime =
    { DateTime: DateTimeOffset
      TimeZone: TimeZoneInfo }

// Declare an array with two elements.
let timeZoneTimes = 
    [| { DateTime = DateTimeOffset.Now; TimeZone = TimeZoneInfo.Local }
       { DateTime = DateTimeOffset.Now; TimeZone = TimeZoneInfo.Local } |]

for timeZoneTime in timeZoneTimes do
    let tz = if isNull timeZoneTime.TimeZone then "<null>" else string timeZoneTime.TimeZone
    printfn $"{tz}: {timeZoneTime.DateTime:G}"
printfn ""

Array.Clear(timeZoneTimes, 1, 1)
for timeZoneTime in timeZoneTimes do
    let tz = if isNull timeZoneTime.TimeZone then "<null>" else string timeZoneTime.TimeZone
    printfn $"{tz}: {timeZoneTime.DateTime:G}"

// The example displays the following output:
//       (UTC-08:00) Pacific Time (US & Canada): 1/20/2014 12:11:00 PM
//       UTC: 1/20/2014 12:11:00 PM
//
//       (UTC-08:00) Pacific Time (US & Canada): 1/20/2014 12:11:00 PM
//       <null>: 1/1/0001 12:00:00 AM

Public Structure TimeZoneTime
    Private dt As DateTimeOffset
    Private tz As TimeZoneInfo

    Public Sub New(dateTime As DateTimeOffset, timeZone As TimeZoneInfo)
        dt = dateTime
        tz = timeZone
    End Sub

    Public ReadOnly Property DateTime As DateTimeOffset
        Get
            Return dt
        End Get
    End Property

    Public ReadOnly Property TimeZone As TimeZoneInfo
        Get
            Return tz
        End Get
    End Property
End Structure

Module Example1
    Public Sub RunIt()
        ' Declare an array with two elements.
        Dim timeZoneTimes() As TimeZoneTime = {New TimeZoneTime(Date.Now, TimeZoneInfo.Local),
                                              New TimeZoneTime(Date.Now, TimeZoneInfo.Utc)}
        For Each timeZoneTime In timeZoneTimes
            Console.WriteLine("{0}: {1:G}",
                           If(timeZoneTime.TimeZone Is Nothing, "<null>", timeZoneTime.TimeZone),
                           timeZoneTime.DateTime)
        Next
        Console.WriteLine()

        Array.Clear(timeZoneTimes, 1, 1)
        For Each timeZoneTime In timeZoneTimes
            Console.WriteLine("{0}: {1:G}",
                           If(timeZoneTime.TimeZone Is Nothing, "<null>", timeZoneTime.TimeZone),
                           timeZoneTime.DateTime)
        Next
    End Sub
End Module
' The example displays output like the following:
'       (UTC-08:00) Pacific Time (US & Canada): 1/20/2014 12:11:00 PM
'       UTC: 1/20/2014 12:11:00 PM
'       
'       (UTC-08:00) Pacific Time (US & Canada): 1/20/2014 12:11:00 PM
'       <null>: 1/1/0001 12:00:00 AM

Poznámky

Tato metoda resetuje každý prvek v poli na výchozí hodnotu typu elementu. Nastaví prvky referenčních typů (včetně String prvků) na nulla nastaví prvky hodnotových typů na výchozí hodnoty uvedené v následující tabulce.

Typ	Hodnota
Boolean	false
Všechny celočíselné a číselné typy s plovoucí desetinou čárkou	0 (nula)
DateTime	DateTime.MinValue
Jiné typy hodnot	Výchozí hodnota polí typu

Rozsah vymazaných prvků se zalamuje z řádku na řádek v multidimenzionálním poli.

Tato metoda vymaže pouze hodnoty prvků; neodstraní samotné prvky. Pole má pevnou velikost; proto nelze přidat ani odebrat prvky.

Tato metoda je operace $O(n)$, kde $n$ je length.