根据可能性计算要执行的随机操作

Question

我有一个包含一些可能操作的枚举

internal enum Action
{
    Stay,
    MoveLeft,
    MoveRight
}

和一个包含此动作当前机会信息的对象

internal class ActionWithPossibility
{
    public Action Action { get; }
    public int ActionChancePercent { get; }

    public ActionWithPossibility(Action action, int actionChancePercent)
    {
        Action = action;
        ActionChancePercent = actionChancePercent;
    }
}

机会从0到100。一系列有机会的行动可能

        List<ActionWithPossibility> actionsWithPossibilities = new List<ActionWithPossibility>() {
            new ActionWithPossibility(Action.Stay, 40),
            new ActionWithPossibility(Action.MoveLeft, 30),
            new ActionWithPossibility(Action.MoveRight, 30)
        };

或

        List<ActionWithPossibility> actionsWithPossibilities = new List<ActionWithPossibility>() {
            new ActionWithPossibility(Action.Stay, 30),
            new ActionWithPossibility(Action.MoveLeft, 10),
            new ActionWithPossibility(Action.MoveRight, 60)
        };

或

        List<ActionWithPossibility> actionsWithPossibilities = new List<ActionWithPossibility>() {
            new ActionWithPossibility(Action.Stay, 30),
            new ActionWithPossibility(Action.MoveLeft, 60),
            new ActionWithPossibility(Action.MoveRight, 10)
        };

有两件事很重要：

• 100种可能性之和

通过此方法调用随机操作时

    public void NextAction(List<ActionWithPossibility> actionsWithPossibilities)
    {
        int randomNumber = random.Next(0, 100);

        // ...

        Action targetAction = null; // ?
    }

有没有一种方法可以计算动作（不使用ifs）？我考虑过这个设置：

• 行动A 30
• 行动B 10
• 行动C60

我可以总结当前行动的前辈，并将得到这个结果

• 行动A 0-30
• 行动B 30-40
• 行动CRest

但是我不知道如何通过代码计算动作。一些帮助会很棒。

这可能是

基于百分比的概率

但正如我之前提到的，可能的行动数量是未知的，所以我不能使用三个if语句。也许有一个技巧是使用一些数学来避免完全使用if语句。

Answer 1

如果你在一个列表中有你的动作，并且想把你生成的随机数映射到正确的对象。你可以这样想：

林克：

actionsWithPossibilities
   .OrderBy(x => x.actionChancePercent) // Sort probabilities in increasing order
   .First(y => randomNumber <= y.actionChancePercent)
   // Find the correct 'bracket' by checking when the 
   // random number passes the thresholds.

Answer 2

int threshold = 0;
int randomNumber = random.Next(0, 100);
for (var i = 0; i < actionsWithPossibilities.Count; i++)
{
    var item = actionsWithPossibilities[i];
    threshold += item.ActionChancePercent;

    if (randomNumber <= threshold)
    {
        //first action that's under the defined threshold is placed in result
        result = item.Action;
        break;
    }
}