This function creates a pie chart. Note that these are generally quite strongly advised against, as people are not good at interpreting relative frequencies on the basis of pie charts.
ggPie(vector, scale_fill = ggplot2::scale_fill_viridis_d())
The vector (best to pass a factor).
The ggplot scale fill function to use for the colors.
A ggplot pie chart.
This function is very strongly based on the Mathematical Coffee post at http://mathematicalcoffee.blogspot.com/2014/06/ggpie-pie-graphs-in-ggplot2.html.