1. 학습
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  2. 강의
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  3. Joining Data with data.table in R
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연습 문제

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.

지침

100 XP
  • Use the funion() (docs) 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.