We can use functions to organize our code and make it easier to understand. One main function can call slightly smaller functions that each have a specific goal. Those functions can call more specific functions if necessary. Each function does a part of a larger task.

Imagine we were making a program that creates a random bag of marbles and describes it to us. We would need to create and describe each marble. We could have a main program that looks like:

def main():
  random_bag = create_random_bag()
  display_bag()

Our create_random_bag function might look like:

def create_random_bag():
   marble1 = create_random_marble()
   marble2 = create_random_marble()
   marble3 = create_random_marble()
   return [marble1, marble2, marble3]

The create_random_marble might contain logic for what the marble looks like, and on the program would go, describing more and more detailed logic. With this kind of structure, our programs become more organized and easy to read.

Now, we’ll practice organizing a program by creating functions.