Array.Clear 方法

參考

定義

命名空間:: System

組件:: System.Runtime.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

多載

Clear(Array)	清除陣列的內容。
Clear(Array, Int32, Int32)	將陣列中的項目範圍設定為每個項目類型的預設值。

Clear(Array)

來源:: Array.CoreCLR.cs

來源:: Array.CoreCLR.cs

來源:: Array.CoreCLR.cs

清除陣列的內容。

public:
 static void Clear(Array ^ array);

public static void Clear (Array array);

static member Clear : Array -> unit

Public Shared Sub Clear (array As Array)

參數

array: Array

要清除的陣列。

例外狀況

ArgumentNullException

array 為 null。

適用於

Clear(Array, Int32, Int32)

來源:: Array.CoreCLR.cs

來源:: Array.CoreCLR.cs

來源:: Array.CoreCLR.cs

將陣列中的項目範圍設定為每個項目類型的預設值。

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)

參數

array: Array

項目需要加以清除的陣列。

index: Int32

要清除之項目範圍的起始索引。

length: Int32

要清除的項目數目。

例外狀況

ArgumentNullException

array 為 null。

IndexOutOfRangeException

index 小於 array 的下限。

-或-

length 小於零。

-或-

index 和 length 的總和大於 array 的大小。

範例

下列範例會 Clear 使用方法來重設一維、二維和三維陣列中的整數值。

using System;

class Example
{
    public static void Main()
    {
        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("Three dimensions (Rank=3):");
        int[, ,] numbers3 = {{{1, 2}, {3, 4}},
                             {{5, 6}, {7, 8}},
                             {{9, 10}, {11, 12}}};

        for (int i = 0; i < 2; 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 < 2; 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
 *
 * Array.Clear(numbers3, 2, 5)
 * 1 2
 * 0 0
 *
 * 0 0
 * 0 8
 */

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

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 ""

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
//
// Array.Clear(numbers3, 2, 5)
// 1 2
// 0 0
//
// 0 0
// 0 8
//

Module Example
    Sub Main()
        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 1
            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()
        
        Console.WriteLine("Array.Clear(numbers3, 2, 5)")
        Array.Clear(numbers3, 2, 5)

        For i As Integer = 0 To 1
            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
'       
'       Array.Clear(numbers3, 2, 5)
'       1 2
'       0 0
'       
'       0 0
'       0 8

下列範例會 TimeZoneTime 定義包含 TimeZoneInfo 欄位和 DateTimeOffset 欄位的結構。然後它會 Clear 呼叫方法，以清除兩個專案陣列 TimeZoneTime 中的一個專案。方法會將清除專案的值 TimeZoneInfo 設定為物件的預設值，也就是 null ，而物件的預設值 DateTimeOffset 則為 DateTimeOffset.MinValue 。

using System;

public struct TimeZoneTime
{
   private DateTimeOffset dt;
   private TimeZoneInfo tz;

   public TimeZoneTime(DateTimeOffset dateTime, TimeZoneInfo timeZone)
   {
      dt = dateTime;
      tz = timeZone;
   }

   public DateTimeOffset DateTime
   { get { return dt; } }

   public TimeZoneInfo TimeZone
   { get { return tz; } }
}

public class Example
{
   public static void Main()
   {
      // Declare an array with two elements.
      TimeZoneTime[] timeZoneTimes = { new TimeZoneTime(DateTime.Now, TimeZoneInfo.Local),
                                       new TimeZoneTime(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 Example
   Public Sub Main()
      ' 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

備註

這個方法會將陣列中的每個專案重設為元素類型的預設值。它會將參考類型的元素設定 (包括 String) 為 null 的專案，並將實數值型別的元素設定為下表所示的預設值。

類型	值
Boolean	`false`
所有整數和浮點數類型	0 (零)
DateTime	DateTime.MinValue
其他實值型別	類型欄位的預設值

清除的專案範圍會從資料列換列到多維度陣列中的資料列。

這個方法只會清除元素的值;它不會刪除專案本身。陣列具有固定大小;因此，無法加入或移除專案。

這個方法是 O (n) 作業，其中 n 是 length 。

適用於

共用方式為

Array.Clear 方法

定義

多載

Clear(Array)

參數

例外狀況

適用於

Clear(Array, Int32, Int32)

參數

例外狀況

範例

備註

適用於

其他資源