Hi,
I have to deal with time-stamped data coming from outside my own time zone, so
the problem is likely poor knowledge of European time zones on my part. But I
am puzzled just the same.
I thought that setting a time zone of "Europe/Copenhagen" would be the same as
"CET" in winter and "CEST" in summer.
This test in winter works as expected:
> a = as.POSIXct("2013-02-25 01:00:00", tz="Europe/Copenhagen"); a
[1] "2013-02-25 01:00:00 CET"
> b = as.POSIXct("2013-02-25 01:00:00", tz="CET"); b
[1] "2013-02-25 01:00:00 CET"
> a-b
Time difference of 0 secs
But this one is summer does not work as I expected:
> c = as.POSIXct("2013-07-25 01:00:00", tz="Europe/Copenhagen"); c
[1] "2013-07-25 01:00:00 CEST"
> d = as.POSIXct("2013-07-25 01:00:00", tz="CEST"); d
[1] "2013-07-25 01:00:00 UTC"
> e = as.POSIXct("2013-07-25 01:00:00", tz="CET"); e
[1] "2013-07-25 01:00:00 CEST"
> c-d
Time difference of -2 hours
> c-e
Time difference of 0 secs
Setting tz to "Europe/Copenhagen" in summer in c first appears to be the same
as setting it to "CEST" because the output is showing "CEST".
But d should then be the same as c, and it is not.
What is happening?
Thanks in advance,
Denis Chabot
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