通过

Random 类

定义

命名空间:
System
程序集:
mscorlib.dll, System.Runtime.Extensions.dll
程序集:
netstandard.dll, System.Runtime.dll
程序集:
System.Runtime.Extensions.dll
程序集:
mscorlib.dll
程序集:
netstandard.dll
Source:
Random.cs
Source:
Random.cs
Source:
Random.cs
Source:
Random.cs
Source:
Random.cs

表示伪随机数生成器，该生成器是一种算法，该算法生成满足特定随机性统计要求的数字序列。

public ref class Random
public class Random
[System.Serializable]
public class Random
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class Random
type Random = class
[<System.Serializable>]
type Random = class
[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type Random = class
Public Class Random
继承
Object
Random
属性
SerializableAttribute ComVisibleAttribute

示例

以下示例创建一个随机数生成器并调用其 NextBytes， Next以及 NextDouble 用于在不同范围内生成随机数序列的方法。

// Instantiate random number generator using system-supplied value as seed.
var rand = new Random();

// Generate and display 5 random byte (integer) values.
byte[] bytes = new byte[5];
rand.NextBytes(bytes);
Console.WriteLine("Five random byte values:");
foreach (byte byteValue in bytes)
    Console.Write("{0, 5}", byteValue);
Console.WriteLine();

// Generate and display 5 random integers.
Console.WriteLine("Five random integer values:");
for (int ctr = 0; ctr <= 4; ctr++)
    Console.Write("{0,15:N0}", rand.Next());
Console.WriteLine();

// Generate and display 5 random integers between 0 and 100.
Console.WriteLine("Five random integers between 0 and 100:");
for (int ctr = 0; ctr <= 4; ctr++)
    Console.Write("{0,8:N0}", rand.Next(101));
Console.WriteLine();

// Generate and display 5 random integers from 50 to 100.
Console.WriteLine("Five random integers between 50 and 100:");
for (int ctr = 0; ctr <= 4; ctr++)
    Console.Write("{0,8:N0}", rand.Next(50, 101));
Console.WriteLine();

// Generate and display 5 random floating point values from 0 to 1.
Console.WriteLine("Five Doubles.");
for (int ctr = 0; ctr <= 4; ctr++)
    Console.Write("{0,8:N3}", rand.NextDouble());
Console.WriteLine();

// Generate and display 5 random floating point values from 0 to 5.
Console.WriteLine("Five Doubles between 0 and 5.");
for (int ctr = 0; ctr <= 4; ctr++)
    Console.Write("{0,8:N3}", rand.NextDouble() * 5);

// The example displays output like the following:
//    Five random byte values:
//      194  185  239   54  116
//    Five random integer values:
//        507,353,531  1,509,532,693  2,125,074,958  1,409,512,757    652,767,128
//    Five random integers between 0 and 100:
//          16      78      94      79      52
//    Five random integers between 50 and 100:
//          56      66      96      60      65
//    Five Doubles.
//       0.943   0.108   0.744   0.563   0.415
//    Five Doubles between 0 and 5.
//       2.934   3.130   0.292   1.432   4.369

// Instantiate random number generator using system-supplied value as seed.
let rand = Random()

// Generate and display 5 random byte (integer) values.
let bytes = Array.zeroCreate 5
rand.NextBytes bytes
printfn "Five random byte values:"
for byte in bytes do
    printf "%5i" byte
printfn ""

// Generate and display 5 random integers.
printfn "Five random integer values:"
for _ = 0 to 4 do
    printf $"{rand.Next(),15:N0}" 
printfn ""

// Generate and display 5 random integers between 0 and 100.
printfn "Five random integers between 0 and 100:"
for _ = 0 to 4 do
    printf $"{rand.Next 101,8:N0}"
printfn ""

// Generate and display 5 random integers from 50 to 100.
printfn "Five random integers between 50 and 100:"
for _ = 0 to 4 do
    printf $"{rand.Next(50, 101),8:N0}"
printfn ""

// Generate and display 5 random floating point values from 0 to 1.
printfn "Five Doubles."
for _ = 0 to 4 do
    printf $"{rand.NextDouble(),8:N3}"
printfn ""

// Generate and display 5 random floating point values from 0 to 5.
printfn "Five Doubles between 0 and 5."
for _ = 0 to 4 do
    printf $"{rand.NextDouble() * 5.0,8:N3}"

// The example displays output like the following:
//    Five random byte values:
//      194  185  239   54  116
//    Five random integer values:
//        507,353,531  1,509,532,693  2,125,074,958  1,409,512,757    652,767,128
//    Five random integers between 0 and 100:
//          16      78      94      79      52
//    Five random integers between 50 and 100:
//          56      66      96      60      65
//    Five Doubles.
//       0.943   0.108   0.744   0.563   0.415
//    Five Doubles between 0 and 5.
//       2.934   3.130   0.292   1.432   4.369

Module Example
   Public Sub Main()
      ' Instantiate random number generator using system-supplied value as seed.
      Dim rand As New Random()
      ' Generate and display 5 random byte (integer) values.
      Dim bytes(4) As Byte
      rand.NextBytes(bytes)
      Console.WriteLine("Five random byte values:")
      For Each byteValue As Byte In bytes
         Console.Write("{0, 5}", byteValue)
      Next
      Console.WriteLine()   
      ' Generate and display 5 random integers.
      Console.WriteLine("Five random integer values:")
      For ctr As Integer = 0 To 4
         Console.Write("{0,15:N0}", rand.Next)
      Next                     
      Console.WriteLine()
      ' Generate and display 5 random integers between 0 and 100.'
      Console.WriteLine("Five random integers between 0 and 100:")
      For ctr As Integer = 0 To 4
         Console.Write("{0,8:N0}", rand.Next(101))
      Next                     
      Console.WriteLine()
      ' Generate and display 5 random integers from 50 to 100.
      Console.WriteLine("Five random integers between 50 and 100:")
      For ctr As Integer = 0 To 4
         Console.Write("{0,8:N0}", rand.Next(50, 101))
      Next                     
      Console.WriteLine()
      ' Generate and display 5 random floating point values from 0 to 1.
      Console.WriteLine("Five Doubles.")
      For ctr As Integer = 0 To 4
         Console.Write("{0,8:N3}", rand.NextDouble())
      Next                     
      Console.WriteLine()
      ' Generate and display 5 random floating point values from 0 to 5.
      Console.WriteLine("Five Doubles between 0 and 5.")
      For ctr As Integer = 0 To 4
         Console.Write("{0,8:N3}", rand.NextDouble() * 5)
      Next                     
   End Sub
End Module
' The example displays output like the following:
'    Five random byte values:
'      194  185  239   54  116
'    Five random integer values:
'        507,353,531  1,509,532,693  2,125,074,958  1,409,512,757    652,767,128
'    Five random integers between 0 and 100:
'          16      78      94      79      52
'    Five random integers between 50 and 100:
'          56      66      96      60      65
'    Five Doubles.
'       0.943   0.108   0.744   0.563   0.415
'    Five Doubles between 0 and 5.
'       2.934   3.130   0.292   1.432   4.369

以下示例生成一个随机整数，该整数用作索引从数组中检索字符串值。

Random rnd = new();
string[] malePetNames = [ "Rufus", "Bear", "Dakota", "Fido",
                        "Vanya", "Samuel", "Koani", "Volodya",
                        "Prince", "Yiska" ];
string[] femalePetNames = [ "Maggie", "Penny", "Saya", "Princess",
                          "Abby", "Laila", "Sadie", "Olivia",
                          "Starlight", "Talla" ];

// Generate random indexes for pet names.
int mIndex = rnd.Next(malePetNames.Length);
int fIndex = rnd.Next(femalePetNames.Length);

// Display the result.
Console.WriteLine("Suggested pet name of the day: ");
Console.WriteLine($"   For a male:     {malePetNames[mIndex]}");
Console.WriteLine($"   For a female:   {femalePetNames[fIndex]}");

// The example displays output similar to the following:
//       Suggested pet name of the day:
//          For a male:     Koani
//          For a female:   Maggie

let rnd = Random()

let malePetNames =
    [| "Rufus"; "Bear"; "Dakota"; "Fido";
        "Vanya"; "Samuel"; "Koani"; "Volodya";
        "Prince"; "Yiska" |]
let femalePetNames = 
    [| "Maggie"; "Penny"; "Saya"; "Princess";
        "Abby"; "Laila"; "Sadie"; "Olivia";
        "Starlight"; "Talla" |]

// Generate random indexes for pet names.
let mIndex = rnd.Next malePetNames.Length
let fIndex = rnd.Next femalePetNames.Length

// Display the result.
printfn "Suggested pet name of the day: "
printfn "   For a male:     %s" malePetNames.[mIndex]
printfn "   For a female:   %s" femalePetNames.[fIndex]

// The example displays output similar to the following:
//       Suggested pet name of the day:
//          For a male:     Koani
//          For a female:   Maggie

Module Example
   Public Sub Main()
      Dim rnd As New Random()
      Dim malePetNames() As String = { "Rufus", "Bear", "Dakota", "Fido", 
                                    "Vanya", "Samuel", "Koani", "Volodya", 
                                    "Prince", "Yiska" }
      Dim femalePetNames() As String = { "Maggie", "Penny", "Saya", "Princess", 
                                         "Abby", "Laila", "Sadie", "Olivia", 
                                         "Starlight", "Talla" }                                      
      
      ' Generate random indexes for pet names.
      Dim mIndex As Integer = rnd.Next(malePetNames.Length)
      Dim fIndex As Integer = rnd.Next(femalePetNames.Length)
      
      ' Display the result.
      Console.WriteLine("Suggested pet name of the day: ")
      Console.WriteLine("   For a male:     {0}", malePetNames(mIndex))
      Console.WriteLine("   For a female:   {0}", femalePetNames(fIndex))
   End Sub
End Module
' The example displays output similar to the following:
'       Suggested pet name of the day:
'          For a male:     Koani
'          For a female:   Maggie

注解

注释

若要生成加密安全的随机数（例如适合创建随机密码的随机数字），请使用类中的 RandomNumberGenerator 一种静态方法。

有关此 API 的详细信息，请参阅 Random 的补充 API 备注。

继承者说明

在 .NET Framework 2.0 及更高版本中，和方法的行为Next()Next(Int32, Int32)已更改，NextBytes(Byte[])因此这些方法不一定调用方法的Sample()派生类实现。 因此，派生自 Random 该目标 .NET Framework 2.0 及更高版本的类还应重写这三种方法。

调用方说明

无法保证类中 Random 随机数生成器的实现在 .NET 的主要版本中保持不变。 因此，不应假定同一种子会在不同版本的 .NET 中生成相同的伪随机序列。

构造函数

名称 说明
Random()

使用默认种子值初始化类的新实例 Random 。
Random(Int32)

使用指定的种子值初始化类的新实例 Random 。

属性

名称 说明
Shared

提供可从任何线程并发使用的线程安全 Random 实例。

方法

名称 说明
Equals(Object)

确定指定的对象是否等于当前对象。

(继承自 Object)
GetHashCode()

用作默认哈希函数。

(继承自 Object)
GetHexString(Int32, Boolean)

创建一个用随机十六进制字符填充的字符串。
GetHexString(Span<Char>, Boolean)

使用随机十六进制字符填充缓冲区。
GetItems<T>(ReadOnlySpan<T>, Int32)

创建一个数组，其中包含从提供的一组选项中随机选择的项。
GetItems<T>(ReadOnlySpan<T>, Span<T>)

用从提供的一组选项中随机选择的项填充指定范围的元素。
GetItems<T>(T[], Int32)

创建一个数组，其中包含从提供的一组选项中随机选择的项。
GetString(ReadOnlySpan<Char>, Int32)

创建一个用随机选择 choices的字符填充的字符串。
GetType()

获取当前实例的 Type。

(继承自 Object)
MemberwiseClone()

创建当前 Object的浅表副本。

(继承自 Object)
Next()

返回非负随机整数。
Next(Int32, Int32)

返回指定范围内随机整数。
Next(Int32)

返回小于指定最大值的非负随机整数。
NextBytes(Byte[])

用随机数填充指定字节数组的元素。
NextBytes(Span<Byte>)

用随机数填充指定字节范围的元素。
NextDouble()

返回一个大于或等于 0.0 且小于 1.0 的随机浮点数。
NextInt64()

返回非负随机整数。
NextInt64(Int64, Int64)

返回指定范围内随机整数。
NextInt64(Int64)

返回小于指定最大值的非负随机整数。
NextSingle()

返回一个大于或等于 0.0 且小于 1.0 的随机浮点数。
Sample()

返回介于 0.0 和 1.0 之间的随机浮点数。
Shuffle<T>(Span<T>)

执行跨度的就地混排。
Shuffle<T>(T[])

执行数组的就地随机排列。
ToString()

返回一个表示当前对象的字符串。

(继承自 Object)

适用于