我有一个动物园时间序列:
z <- structure(c(55282, 55282, 55282, 55283, 55283, 55283, 55283,
55283, 55283, 55283, 55283, 2339.96, 2331.98, 2335.53, 2340.33,
2340.98, 2346.26, 2349.26, 2350.1, 2353.18, 2361.2, 2358.65,
63.3, 54.5, 58.1, 62.9, 63.7, 69.3, 73.2, 74.5, 77.8, 86.3, 84.2,
9.8, 8.4, 9, 9.7, 9.8, 10.6, 11.2, 11.5, 12, 13.3, 13), .Dim = c(11L,
4L), .Dimnames = list(NULL, c("station_id", "ztd", "zwd", "iwv"
)), index = structure(c(14695.875, 14695.9166666667, 14695.9583333333,
14696, 14696.0416666667, 14696.0833333333, 14696.125, 14696.1666666667,
14696.2083333333, 14696.25, 14696.2916666667), format = structure(c("m/d/y",
"h:m:s"), .Names = c("dates", "times")), origin = structure(c(1,
1, 1970), .Names = c("month", "day", "year")), class = c("chron",
"dates", "times")), class = "zoo")
看看它的结构(据我所见)看起来不错:
> str(z)
‘zoo’ series from (03/27/10 21:00:00) to (03/28/10 07:00:00)
Data: num [1:11, 1:4] 55282 55282 55282 55283 55283 ...
- attr(*, "dimnames")=List of 2
..$ : NULL
..$ : chr [1:4] "station_id" "ztd" "zwd" "iwv"
Index: Classes 'chron', 'dates', 'times' atomic [1:11] 14696 14696 14696 14696 14696 ...
..- attr(*, "format")= Named chr [1:2] "m/d/y" "h:m:s"
.. ..- attr(*, "names")= chr [1:2] "dates" "times"
..- attr(*, "origin")= Named num [1:3] 1 1 1970
.. ..- attr(*, "names")= chr [1:3] "month" "day" "year"
数据一切正常:
> z
station_id ztd zwd iwv
(03/27/10 21:00:00) 55282 2339.96 63.3 9.8
(03/27/10 22:00:00) 55282 2331.98 54.5 8.4
(03/27/10 23:00:00) 55282 2335.53 58.1 9.0
(03/28/10 00:00:00) 55283 2340.33 62.9 9.7
(03/28/10 01:00:00) 55283 2340.98 63.7 9.8
(03/28/10 02:00:00) 55283 2346.26 69.3 10.6
(03/28/10 03:00:00) 55283 2349.26 73.2 11.2
(03/28/10 04:00:00) 55283 2350.10 74.5 11.5
(03/28/10 05:00:00) 55283 2353.18 77.8 12.0
(03/28/10 06:00:00) 55283 2361.20 86.3 13.3
(03/28/10 07:00:00) 55283 2358.65 84.2 13.0
但是,当我将数据转换为 xts 时间序列时,其中一个索引(也只有一个)更改为 NA:
> x <- as.xts(z)
> x
station_id ztd zwd iwv
(03/27/10 21:00:00) 55282 2339.96 63.3 9.8
(03/27/10 22:00:00) 55282 2331.98 54.5 8.4
(03/27/10 23:00:00) 55282 2335.53 58.1 9.0
(03/28/10 00:00:00) 55283 2340.33 62.9 9.7
(NA NA) 55283 2340.98 63.7 9.8
(03/28/10 02:00:00) 55283 2346.26 69.3 10.6
(03/28/10 03:00:00) 55283 2349.26 73.2 11.2
(03/28/10 04:00:00) 55283 2350.10 74.5 11.5
(03/28/10 05:00:00) 55283 2353.18 77.8 12.0
(03/28/10 06:00:00) 55283 2361.20 86.3 13.3
(03/28/10 07:00:00) 55283 2358.65 84.2 13.0
这是 2010 年 3 月 28 日 01:00 的数据。我不明白为什么会这样 - 有人有什么想法吗?我最初在一个巨大的数据集(超过 10 年的数据)中发现了这一点,并且在任何其他日期都没有发生过!