(Builds on: Exploratory data analysis (1D))
(Leads to: dplyr and databases, Semi- and anti-joins)
It is extremely rare to only require a single table of data for an analysis. Far more often you will need to combine together multiple sources of information. Interconnected datasets is often called relational because you need to care about the relationships between the datasets.
Here you’ll learn about the keys which define the relationship, and the mutating joins, the first set of tools for working with related dataset.
Introduction [r4ds-13.1]
nycflights13 [r4ds-13.2]
Keys [r4ds-13.3]
Mutating joins [r4ds-13.4]