11. Student Becomes the Teacher

 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)
    total = total /len(numbers)
    return total
    print total
    
def get_average(x):
    homework = average(x["homework"])
 
     #dictionary에서 homework 키를 가진 값의 평균을 구한다.
    
    quizzes = average(x["quizzes"])
    tests = average(x["tests"])
    return 0.1 * homework + 0.3 * quizzes + 0.6 * tests
    # 가중치를 곱해준다
 
def get_letter_grade(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(x):
    results = []
    for item in x:
        results.append(get_average(item))
    return average(results)
 
# 빈 리스트 result에 각 학생들 평균값을 추가한다.
# 그리고 average(results)로 최종 평균을 구한다. 
  
 
students = [lloyd, alice, tyler]
# 학생의 dictionary 값을 포함한 리스트
 
print get_class_average(students)
print get_letter_grade(get_class_average(students))