How to create a line for equal values of x and y in scatterplot in R?

To create a line for equal values of x and y in scatterplot, we can make use of segments function in base R but this can be done after creating the plot with the help of plot function. The segments function has four arguments, x0, y0, x1, and y1, we need to put the same value in x0 and y0 and the same value in x1 and y1 to draw the appropriate line as shown in the below examples.

Example1

Live Demo

> x<-rnorm(10)
> x

Output

[1] -1.14191974 1.11554154 -0.01255755 1.18841175 1.11300329 -0.69925814
[7] -0.88000117 0.67830803 -0.91237446 -1.14223973

Example

Live Demo

> y<-rnorm(10)
> y

Output

[1] -1.69229826 -0.70352587 0.38544874 0.14022473 0.15490539 -0.25938630
[7] 0.15608239 0.16090625 0.05822404 0.26972301

Example

> plot(x,y)
> segments(x0=-0.23,y0=-0.23,x1=0.23,y1=0.23)

Output

Example2

Live Demo

> x<-rpois(10,5)
> x

Output

[1] 5 0 2 9 4 5 6 2 2 2

Example

Live Demo

> y<-rpois(10,5)
> y

Output

[1] 3 3 6 6 7 5 2 1 3 4

Example

> plot(x,y)
> segments(x0=2,y0=2,x1=5,y1=5)

Output