C# 按照比重來隨機 [搬運微調]
阿新 • • 發佈:2020-09-12
本文章時在原文章基礎上添加了一丟丟測試程式碼
***用途,按照比重來進行隨機
測試程式碼:
int viewCount1 = 0; int viewCount0 = 0; for (int i = 0; i < 5000; i++) { List<GameItemRandomObject> shuidiRanObj = new List<GameItemRandomObject>(); shuidiRanObj.Add(newGameItemRandomObject() { item = 0, Weight = 15 }); shuidiRanObj.Add(new GameItemRandomObject() { item = 1, Weight = 10 }); var obj = GetRandomList<GameItemRandomObject>(shuidiRanObj, 1)[0].item; if (obj.Equals(1)) viewCount1 += 1; if(obj.Equals(0)) viewCount0 += 1; } Console.WriteLine($"五千次測試結果: 0比重15共出現{viewCount0}次,1比重10共出現{viewCount1}次");
以下是原文程式碼:
/// <summary> /// 權重物件 /// </summary> public class RandomObject { /// <summary> /// 權重 /// </summary> publicint Weight { set; get; } } public class GameItemRandomObject : RandomObject { public int item { get; set; } }
/// <summary> /// 帶權重的隨機 /// </summary> /// <param name="list">原始列表</param> /// <param name="count">隨機抽取條數</param> /// <returns></returns> public static List<T> GetRandomList<T>(List<T> list, int count) where T : RandomObject { if (list == null || list.Count <= count || count <= 0) { return list; } //計算權重總和 int totalWeights = 0; for (int i = 0; i < list.Count; i++) { totalWeights += list[i].Weight + 1; //權重+1,防止為0情況。 } //隨機賦值權重 System.Random ran = new System.Random(GetRandomSeed()); //GetRandomSeed()隨機種子,防止快速頻繁呼叫導致隨機一樣的問題 List<KeyValuePair<int, int>> wlist = new List<KeyValuePair<int, int>>(); //第一個int為list下標索引、第一個int為權重排序值 for (int i = 0; i < list.Count; i++) { int w = (list[i].Weight + 1) + ran.Next(0, totalWeights); // (權重+1) + 從0到(總權重-1)的隨機數 wlist.Add(new KeyValuePair<int, int>(i, w)); } //排序 wlist.Sort( delegate (KeyValuePair<int, int> kvp1, KeyValuePair<int, int> kvp2) { return kvp2.Value - kvp1.Value; }); //根據實際情況取排在最前面的幾個 List<T> newList = new List<T>(); for (int i = 0; i < count; i++) { T entiy = list[wlist[i].Key]; newList.Add(entiy); } //隨機法則 return newList; } /// <summary> /// 隨機種子值 /// </summary> /// <returns></returns> private static int GetRandomSeed() { byte[] bytes = new byte[4]; System.Security.Cryptography.RNGCryptoServiceProvider rng = new System.Security.Cryptography.RNGCryptoServiceProvider(); rng.GetBytes(bytes); return BitConverter.ToInt32(bytes, 0); }