再来写一个随机数解决方案，对Random再来一次封装-白红宇

再来写一个随机数解决方案，对Random再来一次封装

阅读量：7240 次

发布时间：2019-06-29

本文共 3611 字，大约阅读时间需要 12 分钟。

本文提供对Random的封装，简化并扩展了其功能

获取随机数，确保同时调用不会重复
```
//new Random().Next(5); RandomTask.Next(5);
```

从一个列表中，随机获取其中某个值

List
       
         lsTest = new List
        
                     {                "1","2","3","4","5"            };            string randomValue = RandomTask.PickOne(lsTest);            Console.WriteLine(randomValue);

从一个列表中，随机获取其中多个值

List
       
         someRandomValue = RandomTask.PickAny(lsTest, 3);Console.WriteLine(string.Join(",", someRandomValue));

想按某个概率返回bool值，可以这么写

bool is30Per = RandomTask.PickBoolByProp(0.3);            Console.WriteLine(is30Per);

最复杂的，一个list中有a，b两个数据，a按照70%概率返回而b按30%返回，就这样写

Dictionary
       
         lsTestAB = new Dictionary
        
                     {                {
      "A",0.7 },                { "B",0.3}            };            string aOrb = RandomTask.PickOneByProb(lsTestAB);            Console.WriteLine(aOrb);

源码

public static class RandomTask    {        private static readonly Random _random = new Random();        public static int Next()        {            lock (_random)            {                return _random.Next();            }        }        public static int Next(int max)        {            lock (_random)            {                return _random.Next(max);            }        }        public static int Next(int min, int max)        {            lock (_random)            {                return _random.Next(min, max);            }        }        ///         /// 按概率获取        /// 
        ///         /// 
               public static bool PickBoolByProp(double trueProp = 1)        {            if (trueProp > 1)            {                trueProp = 1;            }            if (trueProp < 0)            {                trueProp = 0;            }            Dictionary
       
         wt = new Dictionary
        
                     {               { true , trueProp },               { false , 1 - trueProp }            };            return wt.PickOneByProb();        }        /// 
                 /// 按指定概率获取随机结果        /// 
        /// 
         a 0.8 b 0.1 c 0.1        /// 
         
          随机结果 [a,b,c]
                 public static T PickOneByProb
         
          (this Dictionary
          
            sourceDic)        {            if (sourceDic == null || !sourceDic.Any())            {                return default(T);            }            int seed = (int)(10 / (sourceDic.Values.Where(c => c > 0).Min()));            int maxValue = sourceDic.Values.Aggregate(0, (current, d) => current + (int)(seed * d));            int rNum = Next(maxValue);            int tem = 0;            foreach (KeyValuePair
           
             item in sourceDic)            {                tem += (int)(item.Value * seed);                if (tem > rNum)                {                    return item.Key;                }            }            return default(T);        }        /// 
             /// 随机从List中获取一项 /// 
        /// 
                    /// 
                    /// 
                    public static T PickOne
            
             (this List
             
               source) { if (source == null || !source.Any()) { return default(T); } return source[Next(source.Count)]; } /// 
               /// /// 
 /// 
               /// 
               /// 
               /// 
               public static List
              
                PickAny
               
                (this List
                
                  source, int c) { if (source == null || !source.Any()) { return default(List
                 
                  ); } if (source.Count <= c) { return source; } List
                  
                    ls = new List
                   
                    (); for (int i = 0; i < c; i++) { var t = source.PickOne(); if (!ls.Contains(t)) { ls.Add(t); } } return ls; } }