[R] Diff time returns 2 hours when there is 1

[PIKAL Petr]

Hi

You are bitten by DST - daylight savings time. You need to use either timezones which do not have DST or adopt your code to the fact that twice a year one hour takes 2 hour and one hour is missing.

see CEST and CET difference

> time
[1] "1999-10-31 01:00:00 CEST" "1999-10-31 02:00:00 CEST"
[3] "1999-10-31 03:00:00 CET"  "1999-10-31 04:00:00 CET"
>

Until policy makers do not discard DST it will continue to exist.

Cheers
Petr


> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Jue
> Lin-Ye
> Sent: Tuesday, January 13, 2015 12:38 PM
> To: r-help at r-project.org
> Subject: [R] Diff time returns 2 hours when there is 1
>
> Greetings! I am analysing my data and checking for gaps over 1 hour and
> come across the problem that R tells me that there are many 2 hour
> gaps.
> When I go into details, I don't see any of these lapses. Is it
> something with the diff() function?
>
> You can see what I am saying, below:
>
> ​M<-matrix(c(1999,10,31,1,
>             1999,10,31,2,
>             1999,10,31,3,
>             1999,10,31,4),4,4,byrow=T)
> colnames(M)<-c("YY","MM","DD","HH")
> time<-ISOdatetime(M[,"YY"],M[,"MM"],M[,"DD"],M[,"HH"],0,0)
> print(diff(time))
> >Time differences in hours
> [1] 1 2 1
>
> ​Has anyone ever seen something like this? I mean, diff() is one of the
> basic functions of R, so it is probable that many people has seen
> something similar, before. However, somehow, I can't find an answer
> string on stackexchange or analogous pages.​
>
> ​Thanks in advance!​
>
> --
> Jue Lin-Ye
>
>       [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> and provide commented, minimal, self-contained, reproducible code.

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