24.7 Vectorise

• vectorisation means finding the existing R function that is implemented in C and most closely applies to your problem
• Vectorised functions that apply to many scenarios
  • rowSums(), colSums(), rowMeans(), and colMeans()
  • Vectorised subsetting can lead to big improvements in speed
  • cut() and findInterval() for converting continuous variables to categorical
  • Be aware of vectorised functions like cumsum() and diff()
  • Matrix algebra is a general example of vectorisation