[R] Stacked Histogram, multiple lines for dates of news stories?
jim at bitwrit.com.au
Tue Jun 29 11:03:18 CEST 2010
On 06/29/2010 01:04 AM, Simon Kiss 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:
> 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.
I had to think about this for a while, but the following may be what you
want. It also gave me an idea for a new plot. Thanks.
hist(as.numeric(test_df$test2[test_df$test=="Globe and Mail"]),
main="Date of articles",xlab="Year",ylab="Journal",axes=FALSE)
axis(2,at=1:3,labels=c("Globe and Mail","Post","Star"))
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