Exercise

Expecting mapped output

When you know that the output of your mapped function is an expected type (here it is a numeric vector) you can leverage the map_*() family of functions to explicitly try to return that object type instead of a list.

Here you will again calculate the mean population of each country, but instead, you will use map_dbl() to explicitly append the numeric vector returned by mean() to your data frame.

Instructions

100 XP

Generate the pop_mean data frame using the map_dbl() function to calculate the population mean for each nested data frame.
Explore the pop_mean data frame using head().