You can use the following methods to plot multiple plots on the same graph in R:

Method 1: Plot Multiple Lines on Same Graph

#plot first line
plot(x, y1, type='l')

#add second line to plot
lines(x, y2)

Method 2: Create Multiple Plots Side-by-Side

#define plotting area as one row and two columns
par(mfrow = c(1, 2))

#create first plot
plot(x, y1, type='l')

#create second plot
plot(x, y2, type='l')

Method 3: Create Multiple Plots Stacked Vertically

#define plotting area as two rows and one column
par(mfrow = c(2, 1))#create first plot
plot(x, y1, type='l')

#create second plot
plot(x, y2, type='l')

The following examples show how to use each method in practice.

Example 1: Plot Multiple Lines on Same Graph

The following code shows how to plot two lines on the same graph in R:

#define data to plot
x <- 1:10
y1 <- c(2, 4, 4, 5, 7, 6, 5, 8, 12, 19)
y2 <- c(2, 2, 3, 4, 4, 6, 5, 9, 10, 13)

#plot first line
plot(x, y1, type='l', col='red', xlab='x', ylab='y')

#add second line to plot
lines(x, y2, col='blue')

Example 2: Create Multiple Plots Side-by-Side

The following code shows how to use the par() argument to plot multiple plots side-by-side:

#define data to plot
x <- 1:10
y1 <- c(2, 4, 4, 5, 7, 6, 5, 8, 12, 19)
y2 <- c(2, 2, 3, 4, 4, 6, 5, 9, 10, 13)

#define plotting area as one row and two columns
par(mfrow = c(1, 2))

#create first line plot
plot(x, y1, type='l', col='red')

#create second line plot
plot(x, y2, type='l', col='blue', ylim=c(min(y1), max(y1)))

Note that we used the argument in the second plot to ensure that the two plots had the same y-axis limits.

Example 3: Create Multiple Plots Stacked Vertically

The following code shows how to use the par() argument to plot multiple plots stacked vertically:

#define data to plot
x <- 1:10
y1 <- c(2, 4, 4, 5, 7, 6, 5, 8, 12, 19)
y2 <- c(2, 2, 3, 4, 4, 6, 5, 9, 10, 13)

#define plotting area as two rows and one column
par(mfrow = c(2, 1), mar = c(2, 4, 4, 2))
#create first line plot
plot(x, y1, type='l', col='red')

#create second line plot
plot(x, y2, type='l', col='blue', ylim=c(min(y1), max(y1)))

Note that we used the mar argument to specify the (bottom, left, top, right) margins for the plotting area.

Note: The default is mar = c(5.1, 4.1, 4.1, 2.1)

Additional Resources

The following tutorials explain how to perform other common tasks in R: