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[jim holtman]

use POSIXct instead of Date:


> x <- c("2013-12-12 12:00:00", "2013-12-15 03:15:23")
> # convert using as.POSIXct
>
> times <- as.POSIXct(x, format = "%Y-%m-%d %H:%M:%S")
> times
[1] "2013-12-12 12:00:00 EST" "2013-12-15 03:15:23 EST"
>
> difftime(times[2], times[1], units = 'secs')
Time difference of 227723 secs
>
>

Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.


On Wed, Dec 18, 2013 at 9:24 PM, Lydia Keppler <lydiakeppler at gmail.com> wrote:
> Hi there,
>
> I am new to R and programming in general and am looking for help with
> writing a function with dates and times. I have checked around but am still
> a bit stuck.
>
> Basically, I have data in the format "dd/mm/YYYY HH:MM" and I have to
> calculate how much time has passed between various events.
>
> I have given the following command ( where "date" is the column in my data
> frame that indicates the date and time)
> date=as.Date.factor(date,format="%d/%m/%Y %H:%M")
> However, this displays only the date, without the time.
>
> I also have tried:
> date=substr(argo1$date,1,907)
> And it shows the date and time.
>
> However, when I try to find the difference between two dates i.e.the time
> that has passed with the command: difftime(date[2],date[3],unit="secs"), it
> returns that 0 seconds have passed.
>
> When I try to find the difference with the command:
> date[3]-date[2]
> it tells me Error in date[3] - date[2] : non-numeric argument to binary
> operator
>
> The class(date) is "character".
>
> Any idea what I am doing wrong?
> Thank you very much in advance!
>
>
> On 19 December 2013 15:22, <r-help-request at r-project.org> wrote:
>
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