Array.Clear 方法

定义

命名空间:: System

程序集:: netstandard.dll, System.Runtime.dll

程序集:: mscorlib.dll, System.Runtime.dll

程序集:: System.Runtime.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

重要

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重载

名称	说明
Clear(Array)	清除数组的内容。
Clear(Array, Int32, Int32)	将数组中的元素范围设置为每个元素类型的默认值。

Clear(Array)

Source:: Array.cs

Source:: Array.cs

Source:: Array.CoreCLR.cs

Source:: Array.CoreCLR.cs

Source:: Array.CoreCLR.cs

清除数组的内容。

public:
 static void Clear(Array ^ array);

public static void Clear(Array array);

static member Clear : Array -> unit

Public Shared Sub Clear (array As Array)

参数

array: Array

要清除的数组。

例外

ArgumentNullException

array 是 null。

适用于

Clear(Array, Int32, Int32)

Source:: Array.cs

Source:: Array.cs

Source:: Array.CoreCLR.cs

Source:: Array.CoreCLR.cs

Source:: Array.CoreCLR.cs

将数组中的元素范围设置为每个元素类型的默认值。

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)

参数

array: Array

需要清除其元素的数组。

index: Int32

要清除的元素范围的起始索引。

length: Int32

要清除的元素数。

例外

ArgumentNullException

array 是 null。

IndexOutOfRangeException

index小于下限。array

-或-

length 小于零。

-或-

index和大于大小length之和array。

示例

以下示例使用 Clear 该方法重置一维、二维和三维数组中的整数值。

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

以下示例定义包含TimeZoneTimeTimeZoneInfo字段和DateTimeOffset字段的结构。然后， Clear 它调用该方法以清除两个元素数组 TimeZoneTime 中的一个元素。该方法将清除的元素的值设置为对象的默认值 TimeZoneInfo ，即 null，对象的默认值 DateTimeOffset ，即 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

注解

此方法将数组中的每个元素重置为元素类型的默认值。它将引用类型的元素（包括 String 元素）设置为 null，并将值类型的元素设置为下表中显示的默认值。

类型	价值
Boolean	`false`
所有整型和浮点数值类型	0 （零）
DateTime	DateTime.MinValue
其他值类型	类型字段的默认值

清除的元素的范围从行换行到多维数组中的行。

此方法仅清除元素的值;它不会删除元素本身。数组的大小固定;因此，无法添加或删除元素。

此方法是一个 $O（n）$ 操作，其中 $n$ 为 length。

适用于

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