We have just created a basic graph, but we need more practice. Let's create another plot using the plot()
command. First we set up a vector of horizontal axis values called X, and then a vector of vertical axis values called Y. Enter the following syntax on the command line:
X <- c(1, 2, 3, 4, 5, 6, 7, 8) Y <- c(2, 6, 7, 10, 17, 19, 23, 29)
Now let's graph Y against X.
plot(X, Y, pch = 16)
You'll get the following graph:
That was simple! However, our graph is very basic. Note that R has decided to create axis ticks every five units on the Y axis. Also, note that if you don't provide horizontal axis values (an x axis), by default R will plot your values against a running index.
Let's start again and enhance the graph. Now, we will plot Y using red points using the following command:
plot(X, Y, type = "o", col = "red", xlab = "MY X LABEL", ylab = "MY Y LABEL")
The argument type="o"
produces symbols joined by straight lines. Now, let's create a title using the title()
command and the arguments font.main
and col.main
to control the title font and colors.
title(main = "PLOT 3", font.main = 2, col.main = "blue")
Let's look at our graph.
As expected, we have created a title in blue and joined each point with a red line segment.
The font number is an integer between 1 and 5, where 1 is plain, 2 is bold, 3 is italic, 4 is bold italic, and 5 is symbol.
Notice how to create a title. The following are the main font options for graphs: