我正在尝试合并两个具有不规则时间戳频率的数据集。我在另一篇文章中跟随了一个例子来尝试使这个工作，但它仍然不会合并。我试图遵循的例子是adding data from an irregular time series to a timeseries with 5-min timesteps。
数据集1
Words <- as.character(c("2016-08-30 15:04:51.97", "2016-08-30 15:04:53.70",
"2016-08-30 15:04:54.26", "2016-08-30 15:04:56.00",
"2016-08-30 15:04:56.55", "2016-08-30 15:04:58.29",
"2016-08-30 15:04:58.85", "2016-08-30 15:05:00.59",
"2016-08-30 15:05:01.15", "2016-08-30 15:05:02.89",
"2016-08-30 15:05:03.45", "2016-08-30 15:05:05.19",
"2016-08-30 15:05:05.75", "2016-08-30 15:05:07.49",
"2016-08-30 15:05:08.04"))
op <- options(digits.secs = 2)
op
Date <- as.POSIXct(Words)
TagID <- rep(2297.2, 15)
Xaxis <- as.numeric(c(13.738267, 13.76611, 13.728986, 13.70624, 13.722799,
13.696131, 13.707635, 13.683349, 13.688462, 13.690102,
13.67994, 13.680669, 13.684442, 13.676477, 13.678154))
Yaxis <- as.numeric(c(14.670887, 14.630401, 14.684383, 14.68586, 14.69338,
14.686517, 14.694365, 14.677797, 14.681285, 14.687439,
14.675471, 14.678207, 14.681899, 14.674103, 14.675745))
Zaxis <- as.numeric(c(10.106183, 10.198599, 10.075378, 10.057535, 10.054841,
10.049604, 10.042946, 10.057003, 10.054044, 10.043906,
10.058976, 10.054471, 10.050245, 10.059166, 10.057288))
Data1 <- data.frame(Date, TagID, Xaxis, Yaxis, Zaxis)
数据集2
Words2 <- as.character(c("2016-08-30 15:05:01.55", "2016-08-30 15:10:01.56"))
Date <- as.POSIXct(Words2)
Speed <- c(0.385031168, 0.389179907)
Direction <- c(239.5721794,229.063366)
Data2 <- data.frame(Date, Speed, Direction)
合并的数据集应如下所示：
# Date TagID Xaxis Yaxis Zaxis Speed Direction
# 1: 2016-08-30 15:04:51.97 2297.2 13.73827 14.67089 10.10618 NA NA
# 2: 2016-08-30 15:04:53.70 2297.2 13.76611 14.63040 10.19860 NA NA
# 3: 2016-08-30 15:04:54.25 2297.2 13.72899 14.68438 10.07538 NA NA
# 4: 2016-08-30 15:04:56.00 2297.2 13.70624 14.68586 10.05753 NA NA
# 5: 2016-08-30 15:04:56.54 2297.2 13.72280 14.69338 10.05484 NA NA
# 6: 2016-08-30 15:04:58.28 2297.2 13.69613 14.68652 10.04960 NA NA
# 7: 2016-08-30 15:04:58.84 2297.2 13.70763 14.69436 10.04295 NA NA
# 8: 2016-08-30 15:05:00.58 2297.2 13.68335 14.67780 10.05700 NA NA
# 9: 2016-08-30 15:05:01.15 2297.2 13.68846 14.68129 10.05404 0.385031 239.5722
# 10: 2016-08-30 15:05:02.89 2297.2 13.69010 14.68744 10.04391 NA NA
# 11: 2016-08-30 15:05:03.45 2297.2 13.67994 14.67547 10.05898 NA NA
# 12: 2016-08-30 15:05:05.19 2297.2 13.68067 14.67821 10.05447 NA NA
# 13: 2016-08-30 15:05:05.75 2297.2 13.68444 14.68190 10.05025 NA NA
# 14: 2016-08-30 15:05:07.49 2297.2 13.67648 14.67410 10.05917 NA NA
# 15: 2016-08-30 15:05:08.03 2297.2 13.67815 14.67574 10.05729 NA NA
将数据帧转换为数据表并将它们合并在一起：
#Merge datasets
library(data.table)
Data1.dt <- data.table(Data1, key="Date")[,Date2:=Date]
Data2.dt <- data.table(Data2)
NewData <- Data1.dt[Data2.dt, list(Date=Date2, Speed, Direction), roll=-Inf][
Data1.dt, list(Date, TagID, Xaxis, Yaxis, Zaxis, Speed, Direction)]
#does not work - error message but this worked in the other example
#Try again
Data1.dt <- data.table(Data1, key="Date")
Data2.dt <- data.table(Data2)
NewData2 <- Data1.dt[Data2.dt, on="Date", list(Date, Speed, Direction), roll=-Inf][
Data1.dt, list(Date, TagID, Xaxis, Yaxis, Zaxis, Speed, Direction)]
#Merges but does not carry the data with it
我缺少什么使它合并两个数据集并随身携带数据？ 请注意，发布原始示例的人遇到了类似问题，但问题是版本问题 - 我使用的是更高版本，所以它不应该成为问题。
R version 3.2.4 Revised (2016-03-16 r70336) -- "Very Secure Dishes"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64 (64-bit)
data.table version 1.10.4
提前感谢您的帮助。