将 UNIX 纪元转换为日期对象

Question

I'm plotting and performing calculations on uniformly distributed time series. The timestamps are currently stored as integers representing the number of seconds since the UNIX epoch (eg 1352068320 ), but Date objects seem more appropriate for plotting. How can I do the conversion?

I've read ?Date , ?as.Date and ??epoch , but seem to have missed that information.

Answer 1

Go via POSIXct and you want to set a TZ there -- here you see my (Chicago) default:

R> val <- 1352068320
R> as.POSIXct(val, origin="1970-01-01")
[1] "2012-11-04 22:32:00 CST"
R> as.Date(as.POSIXct(val, origin="1970-01-01"))
[1] "2012-11-05" 
R> 

Edit: A few years later, we can now use the anytime package:

R> library(anytime)
R> anytime(1352068320)
[1] "2012-11-04 16:32:00 CST"
R> anydate(1352068320)
[1] "2012-11-04"
R> 

Note how all this works without any format or origin arguments .

Answer 2

With library(lubridate) , numeric representations of date and time saved as the number of seconds since 1970-01-01 00:00:00 UTC, can be coerced into dates with as_datetime() :

lubridate::as_datetime(1352068320)

[1] "2012-11-04 22:32:00 UTC"