• ggplot() initializes a ggplot object.

  • aes() Aesthetic mappings describe how variables in the data are mapped to visual properties (aesthetics) of geoms.

  • geom_point() The point geom is used to create scatterplots.

  • geom_area() For each x value, geom_area() displays a y interval defined by 0 and ymax (or 0 and xmax).

  • geom_smooth() For detecting patterns in data.

  • geom_boxplot() The boxplot compactly displays the distribution of a continuous variable.

  • facet_grid() forms a matrix of panels defined by row and column faceting variables.

  • facet_wrap() wraps a 1d sequence of panels into 2d.

  • vars() Just like aes(), vars() is a quoting function that takes inputs to be evaluated in the context of a dataset.

To learn more about ggplot2 https://r4ds.had.co.nz/index.html and http://www.cookbook-r.com/Graphs/