[R] how to calculate time offset between timezones?

From: dankelley <Dan.Kelley_at_dal.ca>
Date: Thu, 10 Jan 2008 07:21:15 -0800 (PST)

#QUESTION# Is there a way to calculate the offset between timezones, e.g. from "AST" to "GMT"? #DETAILS# I am working with data files that use local time, and that indicate the timezone by e.g. "AST" (Atlantic Standard Time, my local time) in a header. I was guessing that

> ISOdatetime(2008,1,1,1,0,0,tz="GMT") -
> ISOdatetime(2008,1,1,1,0,0,tz="AST")

would work, but it gives a difference of 0. However, when I do

> ISOdatetime(2008,1,1,1,0,0,tz="GMT") - ISOdatetime(2008,1,1,1,0,0)

I get a -4h offset, which is correct. The odd thing is, I am in AST time, as shown by the following.

> ISOdatetime(2008,1,1,1,0,0)

[1] "2008-01-01 01:00:00 AST" #SYSTEM# Mac OS X system, with R 2.6.1

#PS#

I am aware that this sort of thing is system dependent, and so there may not be a general solution. But even if I can only get it working on my own particular system, I'd be happy!

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Received on Thu 10 Jan 2008 - 15:24:39 GMT

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