Python实现一个学生成绩系统

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)
    return total/len(numbers)
def get_average(student):
    homework=average(student['homework'])
    quizzes=average(student['quizzes'])
    tests=average(student['tests'])
    return homework*0.1+quizzes*0.3+tests*0.6
def get_letter_grade(score):
    if score>=90:
        return "A"
    elif score>=80 and score<90:
        return "B"
    elif score>=70 and score<80:
        return "C"
    elif score>=60 and score<70:
        return "D"
    else:
        return "F"

get_letter_grade(get_average(lloyd))
def get_class_average(students):
    results=[]
    for s in students:
        results.append(get_average(s))
    return average(results)
print get_class_average([lloyd,alice,tyler])
print get_letter_grade(get_class_average([lloyd,alice,tyler]))