如何在R中转换unix时间戳（毫秒）和时区？

Question

I have data which has two columns time and timezone that have the timestamp of events. Examples are:

time               timezone
1433848856453      10800000

It seems like the timestamp has fractional seconds in the information as well. I don't understand the timezone format but it must be an equivalent unix format. I need to preserve the fractional seconds as well. How do I go from that to something like in R?

2015-01-01 13:34:56.45 UTC

Note: This human readable date is not the actual converted values of the unix timestamp shown.

Answer 1

It looks like the timezone column is the timezone offset, in milliseconds. I assume that means the timezone column will adjust for daylight saving time manually

So you should add the time and timezone columns before converting to POSIXct . You should also set the tz to "UTC" so no DST adjustments will be made to your POSIXct object.

R> time <- 1433848856453
R> timezone <- 10800000
R> options(digits.secs=3)
R> .POSIXct((time+timezone)/1000, tz="UTC")
[1] "2015-06-09 14:20:56.453 UTC"

Answer 2

I think this can be right for you.

aa <- 1433848856453
as.POSIXct(aa/1000, origin="1970-01-01")
[1] "2015-06-09 13:20:56.453 CEST"

Edit

Now I've realized that my code is not reproducible, because of my personal settings, but this can fix it and let you achieve the goal.

options(digits.secs=6)