R programming Plot color-coded map of world leader s age

Question

I am currently working on R programming. I'm new to this field, I want to plot color-coded map of world leader's age.

I want to know how many countries are included in R program? I've looked into the documentation of rworldmap but unfortunately I cant get any list of countries. How can I find this out?

Answer 1

In the structure of the value returned by the getMap function, it appears that column "NAME" stores the name of an area in the map while "SOVEREIGNT" is the name of the corresponding sovereign state.

Follow this code to extract the unique values in both columns:

library(rworldmap)
world_map <- getMap()
areas <- levels(world_map[["NAME"]])
sovereign_states <- levels(world_map[["SOVEREIGNT"]])