using System;using System.Collections.Generic;using Random = UnityEngine.Random;public static class IListExtension{    // 洗牌    public static void Shuffle
    
     (this IList
     
       list)    {        for (var i = list.Count - 1; i >= 0; --i)        {            var index = Random.Range(0, list.Count);            var temp  = list[index];            list[index] = list[i];            list[i]     = temp;        }    }    // 按权重选取    public static T SelectByWeight
      
       (this IList
       
        
         > list)    {        var allWeight = 0;        foreach (var (weight, _) in list)            allWeight += weight;        if (allWeight == 0) return default;        var value = Random.Range(0, allWeight);        foreach (var (weight, item) in list)        {            if (value < weight)                return item;            value -= weight;        }        return default;    }    }