Question

第一关，抱歉没有任何可重现的数据，但我无法弄清楚如何重现这个问题。但我会尽我所能，列出我所做的以及相关信息的逐步清单。任何关于故障排除的想法都将非常感谢。

我的问题是：

我有一个很大的时间序列数据集，我读到了R.我最终转换为动物园，但是现在我把它保存为数据框。使用read.csv我将数据读入R.使用str查看我得到的数据：

> str(Met)
'data.frame':   568354 obs. of  18 variables:
 $ time_local                          : Factor w/ 568354 levels "2006-08-06 03:15:00",..: 1 2 3     4 5 6 7 8 9 10 ...

注意：Met $ time_local是我关心的，我已经删除了str读数的所有其他列。

如果我使用

搜索重复项

Dup<-Met$time_local[duplicated(Met$time_local)]

我什么都没得到

str(Dup)
Factor w/ 568354 levels "2006-08-06 03:15:00",..:

如果我使用strptime将日期/时间数据转换为POSIXlt或POSIXct对象

MetStrp<-strptime(Met$time_local, "%Y-%m-%d %H:%M:%S")
str(MetStrp)
POSIXlt[1:568354], format: "2006-08-06 03:15:00" "2006-08-06 03:20:00" "2006-08-06 03:25:00" ...

然后搜索重复项

Dup<-MetStrp[duplicated(MetStrp)]
> head(Dup)
[1] "2007-03-11 02:00:00" "2007-03-11 02:05:00" "2007-03-11 02:10:00"
[4] "2007-03-11 02:15:00" "2007-03-11 02:20:00" "2007-03-11 02:25:00"
> str(Dup)
 POSIXlt[1:60], format: "2007-03-11 02:00:00" "2007-03-11 02:05:00" "2007-03-11 02:10:00" ...

我现在有60个重复项（当我创建动物园对象时会抛弃它们。）

有趣的是，如果我将POSIXlt格式更改为POSIXct

ct<-as.POSIXct(MetStrp)
str(ct)
POSIXct[1:568354], format: "2006-08-06 03:15:00" "2006-08-06 03:20:00" "2006-08-06 03:25:00" ...

我得到相同的重复但却偏移了一个小时

Dup<-ct[duplicated(ct)]
> head(Dup)
[1] "2007-03-11 01:00:00 PST" "2007-03-11 01:05:00 PST" "2007-03-11 01:10:00 PST"
[4] "2007-03-11 01:15:00 PST" "2007-03-11 01:20:00 PST" "2007-03-11 01:25:00 PST"
> str(Dup)
 POSIXct[1:60], format: "2007-03-11 01:00:00" "2007-03-11 01:05:00" "2007-03-11 01:10:00" ...

如果我选择使用

查找重复的位置

Dup_loc<-which(duplicated(MetStrp) | duplicated(MetStrp,fromLast=TRUE))

我得到120个重复的位置。这最终是POSIXlt和POSIXct重复的组合。

str(Dup_loc)
int [1:120] 62470 62471 62472 62473 62474 62475 62476 62477 62478 62479 ...

POSIXct日期始终为1-2小时，POSIClt日期始终为2-3小时

要查看重复项：

Test<-MetStrp[Dup_loc]


>Test
[1] "2007-03-11 01:00:00" "2007-03-11 01:05:00" "2007-03-11 01:10:00"
[4] "2007-03-11 01:15:00" "2007-03-11 01:20:00" "2007-03-11 01:25:00"
[7] "2007-03-11 01:30:00" "2007-03-11 01:35:00" "2007-03-11 01:40:00"
[10] "2007-03-11 01:45:00" "2007-03-11 01:50:00" "2007-03-11 01:55:00"
[13] "2007-03-11 02:00:00" "2007-03-11 02:05:00" "2007-03-11 02:10:00"
[16] "2007-03-11 02:15:00" "2007-03-11 02:20:00" "2007-03-11 02:25:00"
[19] "2007-03-11 02:30:00" "2007-03-11 02:35:00" "2007-03-11 02:40:00"
[22] "2007-03-11 02:45:00" "2007-03-11 02:50:00" "2007-03-11 02:55:00"
[25] "2008-03-09 01:00:00" "2008-03-09 01:05:00" "2008-03-09 01:10:00"
[28] "2008-03-09 01:15:00" "2008-03-09 01:20:00" "2008-03-09 01:25:00"
[31] "2008-03-09 01:30:00" "2008-03-09 01:35:00" "2008-03-09 01:40:00"
[34] "2008-03-09 01:45:00" "2008-03-09 01:50:00" "2008-03-09 01:55:00"
[37] "2008-03-09 02:00:00" "2008-03-09 02:05:00" "2008-03-09 02:10:00"
[40] "2008-03-09 02:15:00" "2008-03-09 02:20:00" "2008-03-09 02:25:00"
[43] "2008-03-09 02:30:00" "2008-03-09 02:35:00" "2008-03-09 02:40:00"
[46] "2008-03-09 02:45:00" "2008-03-09 02:50:00" "2008-03-09 02:55:00"
[49] "2009-03-08 01:00:00" "2009-03-08 01:05:00" "2009-03-08 01:10:00"
[52] "2009-03-08 01:15:00" "2009-03-08 01:20:00" "2009-03-08 01:25:00"
[55] "2009-03-08 01:30:00" "2009-03-08 01:35:00" "2009-03-08 01:40:00"
[58] "2009-03-08 01:45:00" "2009-03-08 01:50:00" "2009-03-08 01:55:00"
[61] "2009-03-08 02:00:00" "2009-03-08 02:05:00" "2009-03-08 02:10:00"
[64] "2009-03-08 02:15:00" "2009-03-08 02:20:00" "2009-03-08 02:25:00"
[67] "2009-03-08 02:30:00" "2009-03-08 02:35:00" "2009-03-08 02:40:00"
[70] "2009-03-08 02:45:00" "2009-03-08 02:50:00" "2009-03-08 02:55:00"
[73] "2010-03-14 01:00:00" "2010-03-14 01:05:00" "2010-03-14 01:10:00"
[76] "2010-03-14 01:15:00" "2010-03-14 01:20:00" "2010-03-14 01:25:00"
[79] "2010-03-14 01:30:00" "2010-03-14 01:35:00" "2010-03-14 01:40:00"
[82] "2010-03-14 01:45:00" "2010-03-14 01:50:00" "2010-03-14 01:55:00"
[85] "2010-03-14 02:00:00" "2010-03-14 02:05:00" "2010-03-14 02:10:00"
[88] "2010-03-14 02:15:00" "2010-03-14 02:20:00" "2010-03-14 02:25:00"
[91] "2010-03-14 02:30:00" "2010-03-14 02:35:00" "2010-03-14 02:40:00"
[94] "2010-03-14 02:45:00" "2010-03-14 02:50:00" "2010-03-14 02:55:00"
[97] "2011-03-13 01:00:00" "2011-03-13 01:05:00" "2011-03-13 01:10:00"
[100] "2011-03-13 01:15:00" "2011-03-13 01:20:00" "2011-03-13 01:25:00"
[103] "2011-03-13 01:30:00" "2011-03-13 01:35:00" "2011-03-13 01:40:00"
[106] "2011-03-13 01:45:00" "2011-03-13 01:50:00" "2011-03-13 01:55:00"
[109] "2011-03-13 02:00:00" "2011-03-13 02:05:00" "2011-03-13 02:10:00"
[112] "2011-03-13 02:15:00" "2011-03-13 02:20:00" "2011-03-13 02:25:00"
[115] "2011-03-13 02:30:00" "2011-03-13 02:35:00" "2011-03-13 02:40:00"
[118] "2011-03-13 02:45:00" "2011-03-13 02:50:00" "2011-03-13 02:55:00"

据我所见，我在上面看不到任何重复的时间戳。所以我不确定是什么问题，但有些不妥。

据我所知，我所做的就是将因子数据集转换为基于时间的数据集。因此我不知道为什么我在动物园中出现重复错误，并且在看起来没有任何内容时使用duplicated查找重复项。

再次，对此事的任何想法都将不胜感激。

Answer 1

我有三个字给你：“夏令时”。我根据所提供的证据预测，在您所在的地区，2007年3月11日是夏令时转移发生的日期。请注意，它们发生在1-2 AM的时间范围内。

使用strptime会导致数据集中出现重复日期

1 个答案: