Question

以下代码创建一个间隔为16天的10年日期序列。

library(chron)
seq.dates("01/01/2008","12/31/2017", 16)

输出

[1] 01/01/08 01/17/08 02/02/08 02/18/08 03/05/08 03/21/08 04/06/08 04/22/08 05/08/08 
[10] 05/24/08 06/09/08 06/25/08 07/11/08 07/27/08 08/12/08 08/28/08 09/13/08 09/29/08
[19] 10/15/08 10/31/08 11/16/08 12/02/08 12/18/08 **01/03/09** 01/19/09 02/04/09 02/20/09
[28] 03/08/09 03/24/09 04/09/09 04/25/09 05/11/09 ..........
........................
...........................
[208] 01/25/17 02/10/17 02/26/17 03/14/17 03/30/17 04/15/17 05/01/17 05/17/17 06/02/17
[217] 06/18/17 07/04/17 07/20/17 08/05/17 08/21/17 09/06/17 09/22/17 10/08/17 10/24/17
[226] 11/09/17 11/25/17 12/11/17 12/27/17

我希望每年的第一个条目是1月1日，而不是前一年的最后一个条目（示例序列中为BOLD条目）之后的16天以及相应的后续条目之后的一天。

一个很长的路要走就是分别为各个年份创建日期序列，然后将它们合并到一个向量中。我很好奇，有什么办法可以在一行代码中做到这一点。

Answer 1

如何为您工作。使用sapply传递起点矢量，然后使seq.dates执行更多有限的序列。 sapply函数将简化为一个数组。

dates(sapply( seq.dates("01/01/2008", "01/01/2017", by="years") ,
                               function(x) seq.dates(x, to=x+365, by=16, length=23)))
      [,1]     [,2]     [,3]     [,4]     [,5]     [,6]     [,7]     [,8]    
 [1,] 01/01/08 01/01/09 01/01/10 01/01/11 01/01/12 01/01/13 01/01/14 01/01/15
 [2,] 01/17/08 01/17/09 01/17/10 01/17/11 01/17/12 01/17/13 01/17/14 01/17/15
 [3,] 02/02/08 02/02/09 02/02/10 02/02/11 02/02/12 02/02/13 02/02/14 02/02/15
 [4,] 02/18/08 02/18/09 02/18/10 02/18/11 02/18/12 02/18/13 02/18/14 02/18/15
 [5,] 03/05/08 03/06/09 03/06/10 03/06/11 03/05/12 03/06/13 03/06/14 03/06/15
 [6,] 03/21/08 03/22/09 03/22/10 03/22/11 03/21/12 03/22/13 03/22/14 03/22/15
 [7,] 04/06/08 04/07/09 04/07/10 04/07/11 04/06/12 04/07/13 04/07/14 04/07/15
 [8,] 04/22/08 04/23/09 04/23/10 04/23/11 04/22/12 04/23/13 04/23/14 04/23/15
 [9,] 05/08/08 05/09/09 05/09/10 05/09/11 05/08/12 05/09/13 05/09/14 05/09/15
[10,] 05/24/08 05/25/09 05/25/10 05/25/11 05/24/12 05/25/13 05/25/14 05/25/15
[11,] 06/09/08 06/10/09 06/10/10 06/10/11 06/09/12 06/10/13 06/10/14 06/10/15
[12,] 06/25/08 06/26/09 06/26/10 06/26/11 06/25/12 06/26/13 06/26/14 06/26/15
[13,] 07/11/08 07/12/09 07/12/10 07/12/11 07/11/12 07/12/13 07/12/14 07/12/15
[14,] 07/27/08 07/28/09 07/28/10 07/28/11 07/27/12 07/28/13 07/28/14 07/28/15
[15,] 08/12/08 08/13/09 08/13/10 08/13/11 08/12/12 08/13/13 08/13/14 08/13/15
[16,] 08/28/08 08/29/09 08/29/10 08/29/11 08/28/12 08/29/13 08/29/14 08/29/15
[17,] 09/13/08 09/14/09 09/14/10 09/14/11 09/13/12 09/14/13 09/14/14 09/14/15
[18,] 09/29/08 09/30/09 09/30/10 09/30/11 09/29/12 09/30/13 09/30/14 09/30/15
[19,] 10/15/08 10/16/09 10/16/10 10/16/11 10/15/12 10/16/13 10/16/14 10/16/15
[20,] 10/31/08 11/01/09 11/01/10 11/01/11 10/31/12 11/01/13 11/01/14 11/01/15
[21,] 11/16/08 11/17/09 11/17/10 11/17/11 11/16/12 11/17/13 11/17/14 11/17/15
[22,] 12/02/08 12/03/09 12/03/10 12/03/11 12/02/12 12/03/13 12/03/14 12/03/15
[23,] 12/18/08 12/19/09 12/19/10 12/19/11 12/18/12 12/19/13 12/19/14 12/19/15
      [,9]     [,10]   
 [1,] 01/01/16 01/01/17
 [2,] 01/17/16 01/17/17
 [3,] 02/02/16 02/02/17
 [4,] 02/18/16 02/18/17
 [5,] 03/05/16 03/06/17
 [6,] 03/21/16 03/22/17
 [7,] 04/06/16 04/07/17
 [8,] 04/22/16 04/23/17
 [9,] 05/08/16 05/09/17
[10,] 05/24/16 05/25/17
[11,] 06/09/16 06/10/17
[12,] 06/25/16 06/26/17
[13,] 07/11/16 07/12/17
[14,] 07/27/16 07/28/17
[15,] 08/12/16 08/13/17
[16,] 08/28/16 08/29/17
[17,] 09/13/16 09/14/17
[18,] 09/29/16 09/30/17
[19,] 10/15/16 10/16/17
[20,] 10/31/16 11/01/17
[21,] 11/16/16 11/17/17
[22,] 12/02/16 12/03/17
[23,] 12/18/16 12/19/17

我对这个结果感到有些惊讶，因为我认为该值将是一个字符矩阵，但是str显示它是一个日期元素的矩阵。可以通过调用c来删除表面上明显的“矩阵”（实际上是带有标注属性的“日期”）结构：

str(c(dates(sapply( seq.dates("01/01/2008", "01/01/2017", by="years") , function(x) seq.dates(x, to=x+365, by=16, length=23))) ))
 'dates' num [1:230] 01/01/08 01/17/08 02/02/08 02/18/08 03/05/08 ...
 - attr(*, "format")= chr "m/d/y"
 - attr(*, "origin")= num [1:3] 1 1 1970

如何创建以10天为间隔的10年日期序列，每年从1月1日开始

1 个答案: