根據給定的一個概率數組隨機分配概率

　　在程式中有時候需要為一組數據根據自定義的概率數組隨機分配，如圖：

概率數組：

平均分配的效果圖：

　　JS 例子：

  1    function gailv(num) {
  2 
  3         
  4         $(".slider_num").text(0);
  5         $(".slider_num_input").val(0);
  6 
  7         var gls = [0, 0, 0, 0, 0, 0, 0, 0.02, 0.03, 0.04, 0.04, 0.04, 0.04, 0.07, 0.09, 0.10, 0.09, 0.06, 0.08, 0.10, 0.09, 0.06, 0.02, 0.01], //概率
  8             sliders = [],
  9             multi = 0,
 10             remainder = 0,
 11             takeRemainder = 0,
 12             slis = null,
 13             lineSize = 200, //單行最大任務數
 14             nTaskNum = lineSize * 17,
 15             lineTote = lineSize * gls.length; //任務總數
 16 
 17 
 18         if (num > lineTote) {
 19             layer.alert('任務總數最大為' + lineTote);
 20             num = lineTote;
 21         }
 22 
 23         //獲取與dom相對應的數組
 24         for (var a = 0; a < gls.length; a++) {
 25             sliders.push(0);
 26         }
 27 
 28         //隨機分配任務
 29         for (var i = num; i > 0; i--) {
 30 
 31             slis = random(sliders, gls);
 32 
 33             if (sliders[slis] >= lineSize) {
 34                 for (var j = 7; j < sliders.length ; j++) {
 35                     if (sliders[j] < lineSize) {
 36                         sliders[j]++;
 37                         break;
 38                     }
 39                 }
 40                 sliders[slis] = lineSize;
 41             }
 42             else {
 43                 sliders[slis] += 1
 44             }
 45 
 46         }
 47 
 48         //獲取多餘任務數
 49         if (num > nTaskNum) {
 50             multi = num - nTaskNum;
 51         }
 52 
 53         //分配多餘任務數
 54         if (multi > 0) {
 55             remainder = parseInt(multi / 7);
 56             takeRemainder = multi % 7;
 57 
 58             $.each(sliders, function (index, item) {
 59                 if (index <= 6) {
 60                     sliders[index] = remainder;
 61                 }
 62             })
 63             if (takeRemainder > 0) {
 64                 for (var l = 0; l < takeRemainder; l++){
 65                     sliders[l]++;
 66                 }
 67             }
 68         }
 69 
 70         //渲染dom
 71         for (var n = 0; n < sliders.length; n++) {
 72             $("#eq .slider_con").eq(n).find(".slider_num").text(sliders[n]);
 73         }
 74         
 75         $.each(sliders, function (index, item) {
 76             try {
 77                 $("#eq .slider_con").eq(index).find(".slider_num_input").val(item);
 78                 $("#eq .slider_con").eq(index).find("span").slider("value", item);
 79             } catch (e) {
 80             }
 81         });
 82     }
 83 
 84     function random(arr1, arr2) {
 85         var sum = 0,
 86           factor = 0,
 87           random = Math.random();
 88 
 89         for (var i = arr2.length - 1; i >= 0; i--) {
 90             sum += arr2[i]; // 統計概率總和
 91         };
 92 
 93         random *= sum; // 生成概率隨機數
 94 
 95         for (var i = arr2.length - 1; i >= 0; i--) {
 96             factor += arr2[i];
 97             if (random <= factor)
 98                 return i;
 99         };
100         return null;
101     };

 　　C# 例子：

 1    #region 按照給定的nums總數，根據概率數組分配
 2     /// <summary>
 3     /// 按照給定的nums總數，根據概率數組分配 
 4     /// </summary>
 5     /// <param name="nums">總數</param>
 6     /// <param name="gls">概率數組</param>
 7     /// <returns>分配好的int[]</returns>
 8     public static int[] AgeProbability(int nums, double[] gls = null)
 9     {
10         double[] gls1 = { 0, 0, 0, 0, 0, 0, 0.02, 0.03, 0.04, 0.04, 0.04, 0.04, 0.07, 0.09, 0.10, 0.09, 0.06, 0.08, 0.10, 0.09, 0.06, 0.02, 0.01, 0 };
11         if (gls == null)
12             gls = gls1;
13 
14         int[] sliders = new int[gls.Length];
15         for (int i = 0; i < sliders.Length; i++)
16         {
17             sliders[i] = 0;
18         }
19         Random ran = new Random();
20         for (int i = nums; i > 0; i--)
21         {
22             var slis = rans(sliders, gls, ran);
23             sliders[slis] += 1;
24         }
25         return sliders;
26     }
27 
28     private static int rans(int[] sliders, double[] gls, Random ran)
29     {
30         double sum = 0;
31         double actor = 0;
32         double r = ran.NextDouble();
33 
34         for (int i = gls.Length - 1; i >= 0; i--)
35         {
36             sum += gls[i];  //統計概率總和
37         }
38         r *= sum; // 生成概率隨機數
39         for (int i = gls.Length - 1; i >= 0; i--)
40         {
41             actor += gls[i];
42             if (r <= actor)
43                 return i;
44         }
45         return 0;
46     }
47 
48 
49     #endregion