CODEWITHSUNDEEP
r
user2165907
user2165907

Reputation: 1451

strange behavior of as.POSIXct

As working in a big data table I found NA values in a datetime column where they should not be... All these values should be "2014-03-30 02:00:00".

I made some trials:

> as.POSIXct("2014-03-03 02:00:00")
[1] "2014-03-03 02:00:00 CET"
> as.POSIXct("30/03/2014 2:00", format = "%d/%m/%Y %H:%M")
[1] NA
> as.POSIXct("30/03/2014 0:00", format = "%d/%m/%Y %H:%M")
[1] "2014-03-30 CET"
> as.POSIXct("30/03/2014 4:00", format = "%d/%m/%Y %H:%M")
[1] "2014-03-30 04:00:00 CEST"

Any idea why only

as.POSIXct("30/03/2014 2:00", format = "%d/%m/%Y %H:%M")

produces NA?!!

Upvotes: 4

Views: 102

Answers (1)

rmuc8
rmuc8

Reputation: 2989

As I pointed out in my comment, the solution here is to use

as.POSIXct("30/03/2014 2:00", format = "%d/%m/%Y %H:%M", tz = "GMT")

where GMT can be replaced with your respective time zone.

As you already pointed out, the reason is the change from wintertime to summertime

Any time in between

as.POSIXct("30/03/2014 2:00", format = "%d/%m/%Y %H:%M")

and

as.POSIXct("30/03/2014 2:59", format = "%d/%m/%Y %H:%M")

won't work, since this time did not exist in your country (probably in Europe)

Upvotes: 3

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