7. Transforming
作者：Profesor Magallanes
1. Aggregating
2. Reshaping
2.1. Wide to Long
2.1.1. you avoid missing cells
2.1.2. easier for complex plots and some longitudinal methods
2.2. Long to Wide
2.2.1. easier to compute stats for unit of analysis
2.3. These processes help discover issues
2.3.1. key repetitions
2.3.2. key mistypying