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.
Deze oefening maakt deel uit van de cursus
Joining Data with data.table in R
Oefeninstructies
- 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.
Praktische interactieve oefening
Probeer deze oefening eens door deze voorbeeldcode in te vullen.
# Get all countries in either Asia or Europe
___
# Concatenate all data tables
gdp_all <- ___
# Print all unique countries
___