Hi Simon, Here are two ways to do that with ggplot:
qplot(test2, data = test_df, geom = "freqpoly", colour = test, binwidth = 30, drop = F) qplot(test2, data = test_df, geom = "bar", fill = test, binwidth = 30) binwidth is in days. If you want to bin by other intervals (like months), I'd recommend doing so before plotting. Hadley On Mon, Jun 28, 2010 at 10:04 AM, Simon Kiss <sjk...@gmail.com> wrote: > Dear colleagues, > I have extracted the dates of several news stories from a newspaper data > base to chart coverage trends of an issue over time. They are in a data > frame that looks just like one generated by the reproducible code below. > I can already generate a histogram of the dates with various intervals > (months, quarters, weeks years) using hist.Date. However, there are two > other things I'd like to do. > First, I'd like to either create a stacked histogram so that one could see > whether one newspaper really pushed coverage of an issue at a certain point > while others then followed later on in time. Second, or alternatively, I > would like to do a line graph of the same data for the different papers to > represent the same trends. > I guess what I'm finding challenging is that I don't have counts of the > number of stories on each day or in each week or in each month; I just have > the dates themselves. The date.Hist command was very useful in turning > those into bins, but I'd like to push it a bit further and to a stacked > histogram or a multiple line chart. > Can anyone suggest a way to go about doing this? > > I should say, I played around in Hadley Wickham's ggplot package and looked > at his website, and there is a way to render multiple lines here: > http://had.co.nz/ggplot2/scale_date.html > but it was not clear to me how to plot just the dates or an index of the > dates as I don't have a value for the y axis, other than the number of times > a story was published in that time frame. > > Regardless, I hope someone can suggest something. > Yours, > Simon J. Kiss > > test=sample(1:3, 50, replace=TRUE) > test=as.factor(test) > levels(test)=c("Star", "Globe and Mail", "Post") > test2=ISOdatetime(sample(2004:2009, 50, replace=TRUE), sample(1:12, size=50, > replace=TRUE), sample(1:30, 50, replace=TRUE), 0,0,0) > test2=as.Date(test2) > test_df=data.frame(test, test2) > > ********************************* > Simon J. Kiss, PhD > SSHRC and DAAD Post-Doctoral Fellow > John F. Kennedy Institute of North America Studies > Free University of Berlin > Lansstraße 7-9 > 14195 Berlin, Germany > Cell: +49 (0)1525-300-2812, > Web: http://www.jfki.fu-berlin.de/index.html > > ______________________________________________ > R-help@r-project.org 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. > -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ ______________________________________________ R-help@r-project.org 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.
