Write date class as number of days from 1970

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Write date class as number of days from 1970

Manta
Dear all,

I have a dataset with one column being of class Date. When I write the output, I would like that column being written as number of days from 1970-01-01. I could not find anywhere a way to do it.

Thanks,
Marco
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Re: Write date class as number of days from 1970

arun kirshna
Hi,
May be this helps:
set.seed(24)
dat1<- data.frame(date1=sample(seq(as.Date("2012-09-14",format="%Y-%m-%d"),length.out=40,by="day"),20,replace=FALSE), value=sample(1:60,20,replace=TRUE))
dat1$days1<- as.numeric(difftime(dat1$date1,as.Date("1970-01-01")))
#or
library(lubridate)
dat1$days2<- days(dat1$date1)$day
head(dat1)
#       date1 value days1 days2
#1 2012-09-25     6 15608 15608
#2 2012-09-22    34 15605 15605
#3 2012-10-10    44 15623 15623
#4 2012-10-03     9 15616 15616
#5 2012-10-07    14 15620 15620
#6 2012-10-16    42 15629 15629
#or
library(chron)
as.numeric(as.chron(dat1$date1)-chron(0))
 #[1] 15608 15605 15623 15616 15620 15629 15606 15622 15631 15604 15615 15607
#[13] 15626 15624 15635 15619 15601 15598 15636 15599


A.K.

>Dear all,
>
>I have a dataset with one column being of class Date. When I
write the output, I would like that column being written as number of
days from >1970-01-01. I could not find anywhere a way to do it.
>
>Thanks,
>Marco

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Re: Write date class as number of days from 1970

Uwe Ligges-3
In reply to this post by Manta


On 03.05.2013 15:59, Manta wrote:
> Dear all,
>
> I have a dataset with one column being of class Date. When I write the
> output, I would like that column being written as number of days from
> 1970-01-01. I could not find anywhere a way to do it.


as.numeric(x)

where x is the Date object.

Uwe Ligges



> Thanks,
> Marco
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/Write-date-class-as-number-of-days-from-1970-tp4666155.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

______________________________________________
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https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.