[R] Time data

[jim holtman]

It depends on how you want to work with the data.  Here is an example
of converting both to POSIXct and a numeric value:

> x <- c('1:24', '13:46')
> # convert to POSIXct
> x.POSIXct <- as.POSIXct(x, format = '%H:%M')
> x.POSIXct
[1] "2011-04-14 01:24:00 EDT" "2011-04-14 13:46:00 EDT"
>
> # to get a numeric value representing the hour
> x.hour <- do.call(rbind, strsplit(x, ":"))  # create matrix
> # convert to numeric
> mode(x.hour) <- 'numeric'
> # convert to hour
> x.hour %*% c(1, 1/60)
         [,1]
[1,]  1.40000
[2,] 13.76667


On Wed, Apr 13, 2011 at 5:29 PM, Gregory Pierce
<pierce.gregory at gmail.com> wrote:
> Hello fellow R-users,
>
> I have a data set that includes times in the hh:mm format. I am uncertain
> how to tell R that it is time data. Currently when I try to calculate a mean
> with this time subset, I get an error message:
>
>> mean(mar2011stats$TT)
> [1] NA
> Warning message:
> In mean.default(mar2011stats$TT) :
>  argument is not numeric or logical: returning NA
>
> TT is the column label under which I have stored my time data: (for example,
> 1:24 to represent one hour and twenty four minutes).
>
> Do I have to convert everything to minutes so that R can deal with it as it
> would other numerical values?
>
> Thanks,
> Greg
>
>
>
>        [[alternative HTML version deleted]]
>
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?