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.
This exercise is part of the course
Joining Data with data.table in R
Exercise instructions
- Use the
funion()(docs) function to build a newdata.tablecontaining all countries in either Europe or Asia, with each country appearing only once in the result. - Concatenate all
data.tables ingdpand assign it togdp_all. - Use the
unique()function to remove duplicate rows fromgdp_allso that each country occurs only once in the result.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Get all countries in either Asia or Europe
___
# Concatenate all data tables
gdp_all <- ___
# Print all unique countries
___