Add Titles to a Graph in R Programming – title() Function

title() function in R Language is used to add main title and axis title to a graph. This function can also be used to modify the existing titles.

Syntax:
title(main = NULL, sub = NULL, xlab = NULL, ylab = NULL, …)

Parameters:
main: Main title of the graph
sub: Defines subtitles

Returns: Plot after title addition

Example 1:

# R program to add title to a Graph

# Specifying axis values
x<-1:5; y<-x*x

# Creating a plot
plot(x, y, main = "", xlab = "", ylab = "",
     col.axis = "darkgreen")

# Calling title() function
title(main = "Graph ", sub = "Geeksforgeeks article",
      xlab = "X axis", ylab = "Y axis",
      cex.main = 4,   font.main = 3, col.main = "darkgreen",
      cex.sub = 2, font.sub = 3, col.sub = "darkgreen",
      col.lab ="black"
      )

Output:

In above example main title and sub titles are added to the plot. The arguments that can be used to change the font size are as follows:

• cex.main: size for main title
• cex.lab: text size for axis title
• cex.sub: text size of the sub-title

Example 2:

barplot(c(1, 10) )
title(main = "PLOT ", sub = "Geeksforgeeks article",
      xlab = "X axis", ylab = "Y axis",

  # Change the colors
  col.main="darkgreen", col.lab="black", col.sub="darkgreen",

  # Titles in italic and bold
  font.main = 4, font.lab = 4, font.sub = 3,

  # Change font size
  cex.main = 3, cex.lab = 1.7, cex.sub = 2
  )

Output: