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by mapcar 4220 days ago
Does lubridate solve the unintended timezone conversions of POSIXct classes?
1 comments
hadley 4220 days ago
Can you provide a bit more detail?
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mapcar 4220 days ago
In the R Help Desk 2004 (http://www.r-project.org/doc/Rnews/Rnews_2004-1.pdf), Gabor Grothendieck recommends chron over POSIXct classes on account of the time zone conversions which occur when the tz attribute of the latter object is not "GMT". Will this not be a problem with lubridate? Thanks in advance.
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hadley 4220 days ago
I've never found that to be a problem in practice. Do you have an example where it's bitten you in practice?

(Also you should use UTC and not GMT)

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mapcar 4219 days ago
Hi Hadley, yes for instance

> as.chron("1970-01-01")+unclass(as.chron("2001-04-01")) [1] 04/01/01

> as.POSIXct("1970-01-01","EST")+unclass(as.POSIXct("2014-06-01","EST")) [1] "2014-06-01 05:00:00 EST"

If there is any conversion necessary it is difficult to get back the original intended time.

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hadley 4219 days ago
What does adding two dates together mean?
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mapcar 4219 days ago
Isn't this the conventional way of converting variables which have been coerced to their numeric representations back to time/date classes?
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