as.POSIXct before and after 1970
Your OS is? I cannot reproduce this on any of mine. Sone OSes do not support dates before 1970, which would explain the difference. R then has to guess when summer time ended in 1969, and I suspect something is happening inconsistently. Also, "EST" is not a real-world POSIX timezone and may well not be implemented fully.
On Mon, 17 Oct 2005, Omar Lakkis wrote:
Can someone, please, explain the difference in as.POSIXct results before 1970 and on and after 1970 as illustrated below. After 1970, the use of 'EST' or "EST+5EDT' as the timezone does not affect the result of asPOSIXct, but before 1970 on 10/28 the results are different.
as.POSIXct('1970-10-29', tz='EST')+1
[1] "1970-10-29 00:00:01 EST"
as.POSIXct('1970-10-29', tz='EST+5EDT')+1
[1] "1970-10-29 00:00:01 EST"
as.POSIXct('1969-10-29', tz='EST')+1
[1] "1969-10-29 00:00:01 EST"
as.POSIXct('1969-10-29', tz='EST+5EDT')+1
[1] "1969-10-28 23:00:01 EST"
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