[R] Errors and OS Differences with as.POSIXct and as.POSIXlt

[Bill Denney]

Hello,



Dates created with as.POSIXct differ between Windows/Mac and Linux.
Specifically this time that is during a gap when the hour does not exist
due to daylight savings time:



as.POSIXct("2018-03-11 02:09:36", tz="America/New_York")



Gives on Windows:

[1] "2018-03-11 EST"

Gives on Linux (Ubuntu 20.04):

[1] "2018-03-11 01:09:36 EST"



Since the time does not exist, and I think that NA should be returned.



Another issue and difference is that with as.POSIXlt on Linux, the invalid
time is presented:



as.POSIXlt("2018-03-11 02:09", tz="America/New_York")



Gives on Windows:

[1] "2018-03-11 EST"

Gives on Linux:

[1] "2018-03-11 02:09:00 EDT"



(Note that the time provided on Linux does not exist due to daylight
savings time.)



I think that for any invalid time, the result should be the same as an
invalid date:  NA is returned.



What is the intended, appropriate time, and what is the best way to fix
this?



Thanks,



Bill

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