[R] Counting question

[Gabor Grothendieck]

Gabor Grothendieck <ggrothendieck <at> myway.com> writes:

: 
: Adair, Laurence <Laurence.Adair <at> parsons.com> writes:
: 
: > Here is something that sounds simple, but I'm having trouble getting it.  I
: > have a data frame with two columns, the first is date and the second is
: > employee ID.  I'd like to plot date on the horizontal axis, employee ID on
: > the vertical axis, and the number of times the employee appears for the
: > given date as a color.  I've kluged something where I make a table
: > (table(date, id)) and add points to a plot by looping through the rownames
: > (employee ids) of the table.  But certainly there is a better way of doing
: > this??
: 
: In the example below the first three lines create a random test 
: data frame with columns date and id.   
: 
: The fourth line calculates the counts using table, converts it back 
: to a data frame (which has the effect of adding a Freq column) and 
: removes any row with a Freq of 0.  
: 
: The last two lines load package gregmisc and then plot the data 
: using balloonplot from that package.
: 
: set.seed(1)  
: r <- 100 + sample(5, 25, replace = TRUE)
: DF <- data.frame(date = structure(rev(r), class = "Date"), id = r)
: 
: DF2 <- subset(as.data.frame(table(DF)),Freq > 0)
: 
: require(gregmisc)
: with(DF2, balloonplot(date, id, Freq))

and if you still want the color on the plot too add the dotcolor= arg
where the example uses colors of the rainbow:

with(DF2, balloonplot(date, id, Freq, dotcol = rainbow(max(Freq))[Freq]))