Vertical lines between points with ggplot2

Question

I am new to ggplot2 and cannot figure out how to draw vertical dotted grey lines between

the points/dots along the x-axis. Here\'s my example code:

Answer 1

If your actual data is structured like the one used for your example, just add geom_line(aes(group = d3)) to the plot.

ggplot(df, aes(x=x, y=y)) +  
 geom_point() + geom_line(aes(group = d3))