有什么方法可以将日期和时间数据存储在R中的数组中？

Question

I understand that data.frame is of dimension 2 and array is like a matrix in higher dimensions so its elements should of the same data type. I wonder if there is any class or solution to store data including both date and time and numeric values to a variable of dimension 3. Thank you for your help.

Answer 1

All elements in an array must be of the same data type. However; you can convert your date and time to "number of seconds since epoch" and use that since it is numeric. For example how to convert the current time:

>st <- Sys.Time()
>print(st)
[1] "2018-03-30 23:55:56 CDT"
>print(as.numeric(st))
[1] 1522472156

Answer 2

A "POSIXct" vector such as x below can be given dimensions using dim<-

x <- Sys.time() + 1:8
dim(x) <- c(2, 2, 2)

class(x)
## [1] "POSIXct" "POSIXt" 

dim(x)
## [1] 2 2 2

It can alternately be written in this form:

x <- Sys.time() + 1:8
xx <- `dim<-`(x, c(2, 2, 2))