[R] time zone conversion

[Prof Brian Ripley]

The POSIXct/lt functions do this (provided your OS is up to it).

> x <- c("2007-03-01 12:00:00", "2007-03-15 12:00:00",
          "2007-04-01 12:00:00")
> xx <- as.POSIXct(x, tz="EST5EDT")
> format(xx, tz="Europe/London")
[1] "2007-03-01 17:00:00" "2007-03-15 16:00:00" "2007-04-01 17:00:00"

> format(xx, "%Y-%m-%d %H:%M:%S %Z", tz="Europe/London")
[1] "2007-03-01 17:00:00 GMT" "2007-03-15 16:00:00 GMT"
[3] "2007-04-01 17:00:00 BST"

That's Linux, but R 2.7.0 under Windows can do this too (except it labels 
time zones by Windows' names in the last case).


On Mon, 28 Apr 2008, McGehee, Robert wrote:

> Hello,
>
> I'm trying to convert times in the EST/EDT (New York) format to times in
> the GMT/BST (London) and UTC+9 format (Tokyo). That is, if I know what
> time it is in New York, what is local time in London and Tokyo?
>
> Ex:
> Here's the conversion from New York EST/EDT time to London's GMT/BST
> time zone for three days in 2007. Note that the US and London change to
> daylight savings on different days (Tokyo doesn't use daylight savings
> at all), so this conversion is non-trivial.
>
> 2007-03-01 12:00:00 EST = 2007-03-01 17:00:00 GMT
> 2007-03-15 12:00:00 EDT = 2007-03-01 16:00:00 GMT
> 2007-04-01 12:00:00 EDT = 2007-03-01 17:00:00 BST

Don't think so .....

>
> Is any of the time zone/daylight savings information coded up somewhere?
>
> Thanks,
> Robert
>
> Robert McGehee, CFA
> Geode Capital Management, LLC
> One Post Office Square, 28th Floor | Boston, MA | 02109
> Tel: 617/392-8396    Fax:617/476-6389
> mailto:robert.mcgehee at geodecapital.com
>
>
>
> This e-mail, and any attachments hereto, are intended fo...{{dropped:11}}
>
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595