Exercise

Removing duplicates while combining tables

The same list of data tables as the last exercise, gdp, is available in your workspace. Your goal this time is to build a data.table in which each country appears only once, even if it is located in more than one continent.

Instructions

100 XP

Use the funion() function to build a new data.table containing all countries in either Europe or Asia, with each country appearing only once in the result.
Concatenate all data.tables in gdp and assign it to gdp_all.
Use the unique() function to remove duplicate rows fromgdp_all so that each country occurs only once in the result.