Merging and Reshaping Datasets
This chapter covers how to merge datasets, add rows and columns to existing datasets, reshape datasets, and stack and unstack datasets. You will find that some of the analyses you want to do will require stacked data, others will require unstacked data, and still others can use data of either type.
Recipe 4-1. Merging Datasets by a Common Variable
We often have datasets with one or more common variables and want to combine those datasets by matching on a common variable. The merge() function locates matching variables and combines datasets based on these variables.
The following hypothetical ...