Question

I am trying to plot randomization layout in R/ graphics.

Trt <- c(paste ("Trt#", 1:10, sep = ""))
    mydes <- data.frame (block1= sample(Trt), block2 = sample(Trt), block3= sample(Trt), block4= sample( Trt), block5= sample(Trt))
    plot(c(0, NCOL(mydes)), c(0, NROW(mydes)), type= "n", xlab="blocks", ylab = "range")
    grid(lty = 2, col = 1)

    mydes 
       block1 block2 block3 block4 block5
    1  Trt#10  Trt#5  Trt#4  Trt#6  Trt#8
    2   Trt#6  Trt#8  Trt#9  Trt#2  Trt#3
    3   Trt#3  Trt#6  Trt#5 Trt#10  Trt#9
    4   Trt#9  Trt#4  Trt#1  Trt#5  Trt#2
    5   Trt#5  Trt#9  Trt#7  Trt#3  Trt#5
    6   Trt#7  Trt#3  Trt#3  Trt#7  Trt#7
    7   Trt#8 Trt#10  Trt#8  Trt#4  Trt#4
    8   Trt#1  Trt#7 Trt#10  Trt#9  Trt#1
    9   Trt#4  Trt#1  Trt#2  Trt#1 Trt#10
    10  Trt#2  Trt#2  Trt#6  Trt#8  Trt#6

I want to add the text in middle of each grid rectangle. I know I can do it painfully by adding text and specifying coordinates one by one. But I want a generalized solution with some short of loop, that can be applied to any other dimensions as well.

Thanks;

Answer 1

Here is a way of doing it in ggplot:

library(ggplot2)

blocks <- expand.grid(
  x = 1:ncol(mydes),
  y = 1:nrow(mydes)
)

blocks$label <- unname(rapply(mydes, as.character))

ggplot(blocks) + 
  geom_rect(aes(xmin=x-0.4, xmax=x+0.4, ymin=y-0.4, ymax=y+0.4), fill="cyan") +
  geom_text(aes(label=label, x=x, y=y)) +
  xlab("Blocks") + ylab("Treatments")

Since you want to plot this, rather than just printing a table, you may as well use a colour scale to map treatments with the same value:

ggplot(blocks) + 
  geom_rect(aes(xmin=x-0.4, xmax=x+0.4, ymin=y-0.4, ymax=y+0.4, fill=label)) +
  geom_text(aes(label=label, x=x, y=y)) +
  xlab("Blocks") + ylab("Treatments") +
  scale_fill_hue("Treatment", h=c(90, 150))