ylab() to change the text of the axis labels (Figure 8.19):
library(gcookbook) # Load gcookbook for the heightweight data set ggplot(heightweight, aes(x = ageYear, y = heightIn, colour = sex)) + hw_plot <- geom_point() # With default axis labels hw_plot # Set the axis labels + hw_plot xlab("Age in years") + ylab("Height in inches")
By default the graphs will just use the column names from the data frame as axis labels. This might be fine for exploring data, but for presenting it, you may want more descriptive axis labels.
ylab(), you can use
+ hw_plot labs(x = "Age in years", y = "Height in inches")
Another way of setting the axis labels is in the scale specification, like this:
+ hw_plot scale_x_continuous(name = "Age in years")
This may look a bit awkward, but it can be useful if you’re also setting other properties of the scale, such as the tick mark placement, range, and so on.
This also applies, of course, to other axis scales, such as
scale_x_discrete(), and so on.
You can also add line breaks with
\n, as shown in Figure 8.20:
+ hw_plot scale_x_continuous(name = "Age\n(years)")