3.4 Summary

This chapter introduced basic ways of data transformation using the tools provided by the dplyr package.

After working through this chapter, you should be able to use dplyr to:

1. arrange cases (rows) based on one or more criteria;
2. select cases (rows) and variables (columns) from a data table;
3. change and create new variables;
4. compute summary statistics over variables and grouped values;
5. combine multiple commands into pipes to answer questions and create new data tables.

This chapter only covered some essential tools provided by the dplyr package. Take a look at the RStudio cheatsheet on data transformation to check which commands you are now familiar with and which others you can still discover in the future:

Figure 3.7: Data transformation with dplyr from RStudio cheatsheets.

We will encounter more types of data transformation in Chapter 7 on Tidying data and additional dplyr functions in Chapter 8 on Joining data.

Let’s test our knowledge and skills by completing the following exercises.