[英]Generate Random int number outside given List<int>
I am currently trying to find a way to generate a random number outside given list.我目前正在尝试找到一种在给定列表之外生成随机数的方法。
I did this我做了这个
public static int getNewNumberOutsideGivenList(List<int> _list, int _min, int _max)
{
int a = 0;
// I use "Unity.Random", but as C# user you guys can use System.Random function
a = UnityEngine.Random.Range(_min, _max +1);
while (_list.Contains(a))
a = UnityEngine.Random.Range(_min, _max + 1);
return a;
}
It works(kinda) well (I got a short drop in FPS like 10ms after calling this function).它工作(有点)很好(在调用这个函数后,我的 FPS 有一个短暂的下降,比如 10 毫秒)。
However i keep wondering, "is there a better way to do this?"但是我一直想知道,“有没有更好的方法来做到这一点?” or "does System.Linq has a function that is faster than that code?"
或“System.Linq 是否有一个比该代码更快的 function?”
Can you please enlightened me if there exist a better way?如果有更好的方法,你能告诉我吗? Thank yoouuu for your insight.
谢谢你的洞察力。 :)
:)
IMHO you should pre intialize all possible values and than shuffle the list.恕我直言,您应该预先初始化所有可能的值,然后重新排列列表。
using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
static Queue<int> _randomNumbers;
static Program()
{
var min = 0;
var max = 10;
var list = new List<int>();
for (int i = min; i < max; i++)
list.Add(i);
_randomNumbers = new Queue<int>(list.OrderBy(x => Guid.NewGuid()));
}
public static void Main()
{
while (true)
{
var next = GetNext();
if (next is null)
break;
Console.WriteLine(next);
}
}
static int? GetNext() => _randomNumbers.Count == 0 ? null : _randomNumbers.Dequeue();
}
https://dotnetfiddle.net/pBsmyH https://dotnetfiddle.net/pBsmyH
You may find a better shuffle alternative here:您可以在这里找到更好的 shuffle 替代方案:
Edit:编辑:
Here a version without the List<int>
but instead it uses Enumerable.Range(start, count);
这里没有
List<int>
的版本,而是使用Enumerable.Range(start, count);
_randomNumbers = new Queue<int>(Enumerable.Range(min, max - min).OrderBy(x => Guid.NewGuid()));
https://dotnetfiddle.net/S8aDuE https://dotnetfiddle.net/S8aDuE
Edit2:编辑2:
By popular demand here a version with one of the better shuffle alternatives根据大众的需求,这里有一个更好的洗牌替代品之一的版本
using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
static Queue<int> _randomNumbers;
static Random rng = new Random();
static Program()
{
var min = 0;
var max = 10;
var list = new List<int>();
for (int i = min; i < max; i++)
list.Add(i);
Shuffle(list);
_randomNumbers = new Queue<int>(list);
static void Shuffle<T>(IList<T> list)
{
int n = list.Count;
while (n > 1) {
n--;
int k = rng.Next(n + 1);
(list[k], list[n]) = (list[n], list[k]); //Notice: I incorporated @MatthewWatson's idea, so it is slightly different than the one you find on the posted SO page
}
}
}
public static void Main()
{
while (true)
{
var next = GetNext();
if (next is null)
break;
Console.WriteLine(next);
}
}
static int? GetNext() => _randomNumbers.Count == 0 ? null : _randomNumbers.Dequeue();
}
https://dotnetfiddle.net/FRKYyA https://dotnetfiddle.net/FRKYyA
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