On 2023/5/11 23:06, Ivan Krylov wrote:
В Thu, 11 May 2023 22:15:49 +0800
Jinsong Zhao <jsz...@yeah.net> пишет:
> (d <- strptime("1970-01-01 12:00:00 UTC", "%Y-%m-%d %H:%M:%OS", tz
> = ""))
[1] "1970-01-01 12:00:00 CST"
> is.na(d)
[1] TRUE
Glad to see you're making progress! (Sometimes, is.na(strptime(...)) ==
TRUE is what progress looks like.)
is.na.POSIXlt works by converting the "unpacked" date+time into POSIXct
(seconds since 1970-01-01 00:00 UTC) and then checking whether it's NA.
Evidently, as.POSIXct(d) returns NA. (Right?)
What does unclass(d) look like on FreeBSD? Does it contain any NAs
itself, or do they originate somewhere in as.POSIXct(d)?
My current hypothesis is that FreeBSD mktime() doesn't like something
about the timezone, but I may be wrong. Is is.na(strptime(
"1970-01-03 12:00:00 UTC", "%Y-%m-%d %H:%M:%OS", tz = '')) also TRUE?
After I post this thread to the mailing list, I dig into
.Internal(as.POSIXct(d, "")). I think it may be a bug, so I filed a bug
report on R's bugzilla.
Yes, is.na(strptime("1970-01-03 12:00:00 UTC", "%Y-%m-%d %H:%M:%OS", tz
= '')) also TRUE.
I am not familiar with any system function. I just notice that
datetime.c in src/main/ of R 4.3.0 increase 500+ more lines compared to
that of R 4.2.0.
Thank you very much for pointing me to the right direction.
Best,
Jinsong
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