在图表中打印频率（数字）

Question

In R, I would like to insert frequencies (as numbers) in a plot:

my code to create the plot:
par(mar=c(4.5,4.5,9.5,4), xpd=TRUE)  
plot(factor(ArtMehrspr)~Mehrspr_Vielf, data=datProjektMehr, col=terrain.colors(4), 
     bty='L', main="Vielfalt nutzen")  
legend("topright", inset=c(0,-.225), title="Art der Mehrsprachigkeit",  levels(factor(datProjektMehr$ArtMehrspr)), 
       fill=terrain.colors(4), horiz=TRUE)  
par(mar=c(5,4,4,2)+0.1) 

In the plot, 2 columns of my dataframe are depicted: ArtMehrspr and Mehrspr_Vielf . Now what I would like to know is, how many "Kombi" are in category "1", how many "Paral" are in category "1" and so on, and then to print this number in the plot, so that in every box of the plot, I can see the corresponding number of observations. R must know these numbers, otherwise it could not vary the height of the different boxes according to the number of observations. So it cannot be that hard to get these numbers into the plot, can it?

With the command table() , I can get these numbers, but I would have to have 5 table() -commands to get all the numbers. Example for category = 1:

> table(subset(datProjektMehr, Mehrspr_Vielf=="1")$ArtMehrspr)  
einspr  Kombi  Paral  Versc  Wechs   
0          1       9     2       1 

Apparently, you can achieve what I am looking for by adding the command labels = TRUE . But it does not work:

par(mar=c(4.5,4.5,9.5,4), xpd=TRUE, labels = TRUE)  
plot(factor(ArtMehrspr)~Mehrspr_Vielf, data=datProjektMehr, col=terrain.colors(4), 
     bty='L', main="Vielfalt nutzen")  
legend("topright", inset=c(0,-.225), title="Art der Mehrsprachigkeit", levels(factor(datProjektMehr$ArtMehrspr)), 
       fill=terrain.colors(4), horiz=TRUE)  
par(mar=c(5,4,4,2)+0.1)

R gives me the following warning message:

Warning message:
In par(mar = c(4.5, 4.5, 9.5, 4), xpd = TRUE, labels = TRUE) :
  "labels" is not a graphical parameter

Is this not the right command? Does anyone know how to do this?

Answer 1

First of all, the warning informs that there is not a labels argument you can use inside par .

Regarding the plotting of the table output, I'm not aware if there is an easy way of doing this, but I managed a pretty UNreliable and, maybe, inefficient code. In my machine, though, it works every time I run it.

The concept I had in mind is to text all values from your table inside the plot. To do so, coordinates in xx' and yy' had to be estimated. I prefer the term "estimated" instead of "calculated" because I didn't find a way to compute absolute values for the coordinates, due to the fact that the plot method was plot.factor .

So:

    #random data.  DF = datProjektMehr, artmehr = ArtMehrspr, mehrviel = Mehrspr_Vielf 
    DF <- data.frame(artmehr = sample(letters[1:4], 20, T), mehrviel = as.factor(sample(1:5, 20, T)))

    #your code of plotting
    par(mar = c(4.5,4.5,9.5,4), xpd = TRUE)
    plot(factor(artmehr) ~ mehrviel, data = DF, col = terrain.colors(4),
         bty = 'L', main = "Vielfalt nutzen")
    legend("topright", inset=c(0,-.225), title="Art der Mehrsprachigkeit",    levels(factor(DF$artmehr)),
           fill=terrain.colors(4), horiz=TRUE)

    #no need to "table()" many times
    tab = table(DF$artmehr, DF$mehrviel)

    #maximum value of x axis (at least in my machine)
    #I found -through trial and error- that for a factor of n levels, x.max = 1 + (n-1)*0.02
    x.max = 1 + (length(levels(DF$mehrviel)) - 1) * 0.02

    #coordinates of "mehrviel" (as I named it)
    mehrviel.coords = ((cumsum(apply(tab, 2, sum)) / sum(tab)) * x.max) - ((apply(tab, 2, sum) / sum(tab)) / 2)

    #coordinates of "artmehr" (as I named it)
    artmehr.coords <- apply(tab, 2, function(x) { cumsum(x / sum(x)) })
    artmehr.coords <- apply(artmehr.coords, 2, function(x) { x - c(x[1]/2, diff(x)/2) })

    #"text" the values in your table
    #don't plot "0"s
    for(i in 1:ncol(artmehr.coords))
     {
      text(x = mehrviel.coords[i], y = artmehr.coords[,i], labels = ifelse(tab[,i] != 0, tab[,i], ""), cex = 2)
     }

The values of table :

    tab
       1 2 3 4 5
     a 1 1 0 1 0
     b 0 0 2 1 2
     c 1 1 2 1 0
     d 2 0 0 3 2

The plot:

EDIT: 1) "Tidied" the answer. 2) Aadded an extra level to the factor ploted in xx' axis to match your data exactly. 3) text ed the frequencies in the middle of each box.