What is the smartest way to manipulate POSIX for use in ggplot axis? I am trying to create a function for plotting many graphs (One per day) spanning a period of weeks, using POSIX time for the x axis. To do so, I create an additional integer column DF$Day with the day, that I input into the function. Then, I create a subset using that day, which I plot using ggplot2. I figured how to use scale_x_