如何在 C# 中生成不重复的随机数。我有一个数组，我想用 0 到 9 的随机数填充每个房间。每个房间应该有不同的数字。我用这个：
for (int i = 0; i < 20; i++)
{
Random rnd = new Random();
int temp = 0;
temp = rnd.Next(0, 9);
page[i] = temp;
}
但我在每个房间的数组中得到相同的数字。
【问题讨论】：
有了这么小的数字列表可供选择，您只需生成一个包含所有数字的列表，然后shuffle它们。
【讨论】：
您的问题是您在每个循环中都创建了 Random 对象。 Random 对象只能创建一次。试试这个：
Random rnd = new Random(); // <-- This line goes out of the loop
for (int i = 0; i < 20; i++) {
int temp = 0;
temp = rnd.Next(0, 9);
page[i] = temp;
}
【讨论】：
这将创建一个从 1 到 rangeEx 的唯一范围。接下来的两行创建一个随机数生成器，并使用随机数对 IEnumerable 范围进行排序。然后用 ToArray 调用 this 并返回！
private int[] RandomNumber(int rangeEx)
{
var orderedList = Enumerable.Range(1, range);
var rng = new Random();
return orderedList.OrderBy(c => rng.Next()).ToArray();
}
【讨论】：
ArrayList page=new ArrayList();
int random_index;
random rnd = new Random();
for (int i = 0; i < 20; i++)
{
do
{
random_index = rnd.Next(10);
if (!(page.Contains(random_index)))
break;
} while (page.Contains(random_index));
page.Add(random_index);
}
【讨论】：
public Form1()
{
InitializeComponent();
}
int A, B;
string Output;
private void Form1_Load(object sender, EventArgs e)
{
for (int i = 0; i < 20; i++)
{
while (A == B)
{
Random r = new Random();
A = r.Next(1, 6);
}
Output = Output + A;
B = A;
}
textBox1.Text = Output;
}
输出：24354132435213245415（不重复）
【讨论】：
using System;
using System.Collections.Generic;
using System.Linq;
namespace nonRepeatableRndm
{
class Program
{
//variable with the Values
List<string> RandomVal = new List<string>();
//variable to compare the randomly genarated Values
List<string> CompaerbyString = new List<string>();
//Variable that gets Value from the list Values
string DisplayVal;
//instantiates the Random Class
Random r;
//this Method gives Value to the list and initializes th the Random Class
void setVal()
{
//Adding to the list
RandomVal.Add("A");
RandomVal.Add("b");
RandomVal.Add("c");
RandomVal.Add("d");
RandomVal.Add("e");
RandomVal.Add("f");
RandomVal.Add("g");
RandomVal.Add("h");
RandomVal.Add("i");
RandomVal.Add("j");
RandomVal.Add("k");
RandomVal.Add("l");
RandomVal.Add("m");
RandomVal.Add("n");
RandomVal.Add("o");
RandomVal.Add("p");
RandomVal.Add("q");
RandomVal.Add("r");
RandomVal.Add("s");
RandomVal.Add("t");
RandomVal.Add("u");
RandomVal.Add("v");
RandomVal.Add("w");
RandomVal.Add("x");
RandomVal.Add("y");
RandomVal.Add("z");
//Instantiating the Random Method
r = new Random();
}
//This method Gives Out the Random Values
public void DisplayRand()
{
//Setting Random Index
int getIndex = r.Next(0, RandomVal.Count - 1);
//Now we are trying to pass a random value to the String
DisplayVal = RandomVal.ElementAt<string>(getIndex);
//we are testing to see if String in Display is contained in the List that will used Compare
if (!CompaerbyString.Contains(DisplayVal))
Console.WriteLine(DisplayVal.ToUpper());
else
{
try
{
this.DisplayRand();
}
catch(Exception e)
{
Console.WriteLine("You have Reached the End of the list...");
Environment.Exit(0);
}
}
//Adding Corrent DisplayVal's Value to the List for Comparison
CompaerbyString.Add(DisplayVal);
}
//This is Simple method that Calls the Display
void Call()
{
//This For loop is to Ensure we have no Stack Overflow
for ( int i = 0; i < RandomVal.Count-1;i++)
{
this.DisplayRand();
}
}
static void Main(string[] args)
{
Console.WriteLine("Random Values With Out Repeatating Any Value");
//Simple Instantiation
Program dis = new Program();
//Simple Call
dis.setVal();
//Simple Call
dis.Call() ;
Console.ReadLine();
}
}
}
【讨论】：
100% 正确
public int[] UniqeRandomArray(int size , int Min , int Max ) {
int [] UniqueArray = new int[size];
Random rnd = new Random();
int Random;
for (int i = 0 ; i < size ; i++) {
Random = rnd.Next(Min, Max);
for (int j = i; j >= 0 ; j--) {
if (UniqueArray[j] == Random)
{ Random = rnd.Next(Min, Max); j = i; }
}
UniqueArray[i] = Random;
}
return UniqueArray;
}
// 注意是唯一的 [Max - Min > size] 不等于
【讨论】：