Using barplot

Here plot.heights is a matrix:

> plot.heights
     [,1] [,2]
[1,]   74   91
[2,]   26    9

When barplot takes in a 2D data structure, like this, it plots each row as a group.

(Last time, we saw what it does for a 1D structure: simply plot all of them one after the other.)

The return value bp is the same shape as our input data. It tells us where on the x-axis each of the bar centers is.

bp <- barplot(
  plot.heights, 
  beside = T, 
  names = c("GMO germ.","Wild germ.", 
            "GMO fail", "Wild fail"), 
  ylim = c(0, max(plot.heights) + 20), 
  ylab = "Number of seeds")

image.png

Using barplot

Here plot.heights is a matrix:

> plot.heights
     [,1] [,2]
[1,]   74   91
[2,]   26    9

When barplot takes in a 2D data structure, like this, it plots each row as a group.

(Last time, we saw what it does for a 1D structure: simply plot all of them one after the other.)

The return value bp is the same shape as our input data. It tells us where on the x-axis each of the bar centers is.

bp <- barplot(
  plot.heights, 
  beside = T, 
  names = c("GMO germ.","Wild germ.", 
            "GMO fail", "Wild fail"), 
  ylim = c(0, max(plot.heights) + 20), 
  ylab = "Number of seeds")

image.png