Change size of axes title and labels in ggplot2

Question

I have a really simple question, which I am struggling to find the answer to. I hoped someone here might be able to help me.

An example dataframe is presented below:

a <- c(1:10)

b <- c(10:1)

df <- data.frame(a,b)

library(ggplot2)

g = ggplot(data=df) + geom_point(aes(x=a, y=b)) +

  xlab("x axis")

g

I just want to learn how I change the text size of the axes titles and the axes labels.

Answer 1

To change the size of the axes title and labels in ggplot2, you can use the axis.title and axis.text in the theme function as follows: 

theme(axis.text=element_text(size=16),

 axis.title=element_text(size=16,face="bold"))

For example:

library("ggplot2")

ggplot(data = diamonds,aes(x = clarity)) + 

  geom_bar(aes(fill = cut))+ 

  theme_bw()+

  theme(axis.text=element_text(size=10),

  axis.title=element_text(size=12,face="italic"))

Output: