Melting a wide table
A data table named gdp_per_capita containing the gross domestic product (GDP) per capita for countries in Oceania every five years from 1990 to 2010 sourced from the Gapminder foundation is available in your workspace. Your goal is to reshape this data table to the long format so that there is a single column containing all GDP per capita values for each country and year.
Это упражнение является частью курса
Joining Data with data.table in R
Интерактивное практическое упражнение
Попробуйте выполнить это упражнение, дополнив этот пример кода.
# Print gdp_per_capita
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# Reshape gdp_per_capita to the long format
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