8. Part of the Whole


#1

Hi there.

I don’t get how to get rid of this error:

get_class_average([alice]) resulted in an error: maximum recursion depth exceeded

lloyd = {
  "name": "Lloyd",
  "homework": [90.0, 97.0, 75.0, 92.0],
  "quizzes": [88.0, 40.0, 94.0],
  "tests": [75.0, 90.0]
}
alice = {
  "name": "Alice",
  "homework": [100.0, 92.0, 98.0, 100.0],
  "quizzes": [82.0, 83.0, 91.0],
  "tests": [89.0, 97.0]
}
tyler = {
  "name": "Tyler",
  "homework": [0.0, 87.0, 75.0, 22.0],
  "quizzes": [0.0, 75.0, 78.0],
  "tests": [100.0, 100.0]
}

# Add your function below!
def average(numbers):
  total = sum(numbers)
  total = float(total)
  result = total / len(numbers)
  return result

def get_average(student):
  homework = average(student["homework"])
  quizzes = average(student["quizzes"])
  tests = average(student["tests"])
  return 0.1 * average(student["homework"]) +  0.3 * average(student["quizzes"]) + 0.6 * average(student["tests"])

def get_letter_grade(score):
  float(score)
  if score >= 90:
    return "A"
  elif score >= 80:
    return "B"
  elif score >= 70:
    return "C"
  elif score >= 60:
    return "D"
  else:
    return "F"
print get_letter_grade(get_average(lloyd))

def get_class_average(class_list):
  results = []
  for student in class_list:
  	results.append(get_class_average(student))
  return average(results)

Can somebody, please, explain me?


#2

A function calling itself is recursion

In your case, inside get_class_average function you call get_class_average, this will keep going until the maximum depth (amount of time a function can call itself) is reached

sort of like an infinity loop, but with functions and recursion


#3

Thanks for your good explanation. Now I see, but still don’t get how can I append then the function to have the results?


#4

we have get_average() to calculate the average grade of a single student, we get the individual student due to the loop, so we can use get_average as a helper function in get_class_average


#5

Thanks. :slight_smile:


#6

But how are you going to learn this thought process? Like: get_class_average is clearly not the right function to call, why? What i am trying to achieve here? Which function would this require and so forth?

Because now i did this step for you