以亂數進行某段日期區間的抽樣
本文討論假設我們要依照下列條件亂數來進行抽樣，應該怎麼做：
-
- 開始日期：2011-07-20
- 結束日期：2011-07-30
- 每天開始時間：08：00
- 每天結束時間：09：00
- 抽樣數量：10筆
- 格式：yy-MM-dd hh:mm
- 筆者將上述需求除格式外，寫成一個函式以利將來條件改變時得以reuse，程式碼如下：
1: /// <summary>
2: /// 亂數進行日期抽樣
3: /// </summary>
4: /// <param name="StartDate">起始日期</param>
5: /// <param name="DueDate">結束日期</param>
6: /// <param name="StartTime">每日起始時間</param>
7: /// <param name="DueTime">每日結束時間</param>
8: /// <param name="count">抽樣數量</param>
9: /// <returns></returns>
10: private static List<DateTime> GetRandomDate(DateTime StartDate, DateTime DueDate, int StartTime, int DueTime,int count)
11: {
12: List<DateTime> list = new List<DateTime>();
13: if (!(StartDate.CompareTo(DueDate) > 0 || StartTime.CompareTo(DueTime) > 0 || count < 0))
14: {
15: Random ran = new Random();
16: while (list.Count < count)
17: {
18: DateTime dtCurrent = StartDate.AddDays(ran.Next(0
19: , int.Parse(DueDate.Subtract(StartDate).TotalDays.ToString()) - 1));
20: dtCurrent = dtCurrent.AddHours(StartTime).AddMinutes(ran.Next(0, ((DueTime - StartTime) * 60) - 1));
21: if (dtCurrent.Hour.CompareTo(DueTime) < 1)
22: {
23: if (!list.Contains(dtCurrent))
24: {
25: list.Add(dtCurrent);
26: }
27: }
28: }
29: }
30: return list;
31: }
- 下列程式碼示範如何使用GetRandomDate函式：
1: static void Main(string[] args)
2: {
3: List<DateTime> list = GetRandomDate(new DateTime(2011, 7, 20), new DateTime(2011, 7, 30), 8, 9,10);
4: foreach (DateTime dt in list)
5: {
6: Console.WriteLine(string.Format("{0},{1}", list.Count.ToString(), dt.ToString("yy-MM-dd hh:mm")));
7: }
8: Console.ReadKey();
9: }
- 執行結果：
