Exploring world life expectancy
The two data.tables from the previous exercise have been loaded into your workspace:
life_exp: contains the life expectancy of each country in 2010 sourced from the Gapminder foundationcontinents: contains a mapping between each country and the continent(s) they are part of built from information provided by Countries-ofthe-World.com.
Your goal this time is to calculate the average life expectancy across countries within each continent.
This exercise is part of the course
Joining Data with data.table in R
Exercise instructions
Inner join life_exp to continents and calculate the mean() (docs) "years" of life expectancy grouped by the "continent" column.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Calculate average life expectancy per continent:
avg_life_expectancy <- continents[life_exp, on = .(country),
___][, j = ___,
by = ___]
avg_life_expectancy