[R] Working with temporal data

[Sérgio Nunes]

Please note that I do not have values, only dates that represent
occurrences (one link, one date, one occurrence). This means that the
same date might appear several times in different rows. Nevertheless,
I think I can manage this based on your samples.

Thanks,

Sérgio Nunes


On 2/15/07, jim holtman <jholtman at gmail.com> wrote:
> Here is a start on what you want to do.  This generates some test data and
> then does a couple of summaries:
>
>
>
> > # generate some data
> > N <- 1000
> > x <- data.frame(date=as.character(20070000 + sample(1:4, N, TRUE) * 100 +
> sample(1:31, N, TRUE)),
> +     value=runif(N))
> > head(x)  # display the data
>        date      value
> 1 20070124 0.07904540
> 2 20070117 0.17864565
> 3 20070109 0.86078870
> 4 20070205 0.93952259
> 5 20070112 0.87904425
> 6 20070323 0.01717623
> > # assuming you read it in as character, convert to Date for processing
> > x$date <- as.Date(strptime(x$date, "%Y%m%d"))
> > x <- x[order(x$date), ] # order by date for plotting
> > plot(x$date, x$value, type='l')   # plot the data
> > # show counts by month
> > table(months(x$date))
>
>    April February  January    March
>      238      236      253      237
> > # average by month
> > aggregate(x$value, list(months(x$date)), mean)
>    Group.1         x
> 1    April 0.4791387
> 2 February 0.5010831
> 3  January 0.5114135
> 4    March 0.4695668
> >
>
>
>
> On 2/15/07, Sérgio Nunes <snunes at gmail.com> wrote:
> >
> > Hi,
> >
> > I have several files with data in this format:
> >
> > 20070102
> > 20070102
> > 20070106
> > 20070201
> > ...
> >
> > The data is sorted and each line represents a date (YYYYMMDD). I would
> > like to analyze this data using R. For instance, I would like to have
> > a histogram by year, month or day.
> >
> > I've already made a simple Perl script that aggregates this data but I
> > believe that R can be much more powerful and easy on this kind of
> > work.
> >
> > Any suggestions on where to start?
> >
> > Thanks in advance,
> > Sérgio Nunes
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch 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.
> >
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem you are trying to solve?