Instead of using breaks="30 mins" construct the breaks explicitly with
seq() so you can control the start point. E.g.,
> init_day <- as.POSIXct("2018-02-01-00-00", format="%Y-%m-%d-%H-%M",
tz="Etc/GMT-1")
> fin_day <- as.POSIXct("2018-02-01-02-00", format="%Y-%m-%d-%H-%M",
tz="Etc/GMT-1")
> mydf
7 dicembre 2020 7.36
A: r-help@r-project.org; Richard O'Keefe; Stefano Sofia
Cc: r-help mailing list
Oggetto: Re: [R] change frequency of wind data correctly
Beware of missing or extra records with these approaches. Also may be tricky to
get the time aligned to the hour properly.
On December 6,
Beware of missing or extra records with these approaches. Also may be tricky to
get the time aligned to the hour properly.
On December 6, 2020 9:12:01 PM PST, Richard O'Keefe wrote:
>To be honest, I would do this one of two ways.
>
>(1) Use ?decimate from library(signal),
>decimating by a fa
To be honest, I would do this one of two ways.
(1) Use ?decimate from library(signal),
decimating by a factor of three.
(2) Convert the variable to an (n/3)*3 matrix using
as.matrix then use rowMeans or apply.
On Thu, 3 Dec 2020 at 06:55, Stefano Sofia
wrote:
> Dear list users,
> I hav
t
> ---Oo-oO
>
> ____________
> Da: Jim Lemon [drjimle...@gmail.com]
> Inviato: giovedì 3 dicembre 2020 4.41
> A: Stefano Sofia
> Cc: r-help mailing list
> Oggetto: Re: [R] change frequency of wind data correctly
>
> H
06 7743
E-mail: stefano.so...@regione.marche.it
---Oo-oO
Da: Jim Lemon [drjimle...@gmail.com]
Inviato: gioved? 3 dicembre 2020 4.41
A: Stefano Sofia
Cc: r-help mailing list
Oggetto: Re: [R] change frequency of wind data correctly
Hi
Hi Stefano
I think either of these does what you need...
1: This gets the interval column as you want it, but utilises the lubridate
package:
library(lubridate)
mydf$interval = ceiling_date(mydf$data_POSIX, unit="30 minutes”)
2: Alternative in base R is a bit more long winded: convert the da
-
Da: Jim Lemon [drjimle...@gmail.com]
Inviato: gioved? 3 dicembre 2020 4.41
A: Stefano Sofia
Cc: r-help mailing list
Oggetto: Re: [R] change frequency of wind data correctly
Hi again,
Didn't realize that the example didn't even span a full day.
arche.it
---Oo-oO
Da: Jim Lemon [drjimle...@gmail.com]
Inviato: giovedì 3 dicembre 2020 4.41
A: Stefano Sofia
Cc: r-help mailing list
Oggetto: Re: [R] change frequency of wind data correctly
Hi again,
Didn't realize that the example didn't even
: giovedì 3 dicembre 2020 4.41
A: Stefano Sofia
Cc: r-help mailing list
Oggetto: Re: [R] change frequency of wind data correctly
Hi again,
Didn't realize that the example didn't even span a full day.
ssdf<-read.table(text="date_POSIX time_POSIX vmax
2018-02-01 00:00:00 27
2018-02-01
Hi again,
Didn't realize that the example didn't even span a full day.
ssdf<-read.table(text="date_POSIX time_POSIX vmax
2018-02-01 00:00:00 27
2018-02-01 00:10:00 41
2018-02-01 00:20:00 46
2018-02-01 00:30:00 39
2018-02-01 00:40:00 34
2018-02-01 00:50:00 32
2018-02-01 01:00:00 37
2018-02-
Hi Stefano,
I read in your date-time as two separate fields for convenience. You
can split your single field at the space to get the same result.
ssdf<-read.table(text="date_POSIX time_POSIX vmax
2018-02-01 00:00:00 27
2018-02-01 00:10:00 41
2018-02-01 00:20:00 46
2018-02-01 00:30:00 39
2018-
Dear list users,
I have wind data with frequency of 10 minutes (three years data). For
simplicity let me use only max wind speed.
I need to reduce the frequency to 30 minutes, at 00 (taking the mean of data
at 40, 50 and 00 minutes) and at 30 (taking the mean of data at 10, 20 and 30
minutes)
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