Python 入门教程 10 ---- Student Becomes the Teacher

第一节

1 练习

1 设置三个的字典分别为lloyd，alice，tyler

2 对每一个的字典的key都设置为"name"，"homework" , "quizzes", "tests"

3 每个字典的key为"name"对应的为人的名字，其他key对应的值为空列表

# three dictionaries
lloyd = {"name":"Lloyd" , "homework":[] , "quizzes":[] , "tests":[]}
alice = {"name":"Alice" , "homework":[] , "quizzes":[] , "tests":[]}
tyler = {"name":"Tyler" , "homework":[] , "quizzes":[] , "tests":[]}

第二节

1 练习：把第一个字典lloyd中的三个空列表的值设置对应如下

Homework: 90.0, 97.0, 75.0, 92.0
                    Quizzes: 88.0, 40.0, 94.0
                    Test Scores: 75.0, 90.0

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]
}

第三节

1 练习：把lloyd , alice , tyler三个字典放到列表students中

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]
}
# you code here
students = [lloyd , alice , tyler]

第四节

1 练习：按照以下的格式，打印出students列表中的三个字典

Lloyd
[90, 97, 75, 92]
[88, 40, 94]
[75, 90]

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]
}
# you code here
students = [lloyd , alice , tyler]
# you code hrre
for my_list in students:
    for str in my_list:
        print my_list[str]

第五节

1 练习

1 对于每一个数字列表，我们可以求其平均值，比如    average([0]) #0.0，average([0,2]) #1.0，average([0,1]) #0.5

2 写一个函数average，参数是列表lst，求其平均值并以float形式输出

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(lst):
    sum = 0
    for num in lst:
        sum = sum+num
    return float(sum)/len(lst)

第六节

1 介绍了我们经常需要去求很多数的平均值，比如80 * 0.4 + 86 * 0.6

2 练习：写一个函数get_average，参数是一个学生字典，使用如下比例Homework  10%, quizzes 30% tests60%算出这个学生的平均得分

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(lst):
    sum = 0
    for num in lst:
        sum = sum+num
    return float(sum)/len(lst)
# function get_average
def get_average(stu):
    return 0.1*average(stu["homework"])+0.3*average(stu["quizzes"])+0.6*average(stu["tests"])
 

第七节

1 练习

1 写一个函数get_letter_grade，参数是score，按照以下的规则返回对应的等级

Scores 90 or above: return "A"
If 80 <= score < 90: return "B"
If 70 <= score < 80: return "C"
If 60 <= score < 70: return "D"
If score < 60: return "F"

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(lst):
    sum = 0
    for num in lst:
        sum = sum+num
    return float(sum)/len(lst)

# function get_average
def get_average(stu):
    return 0.1*average(stu["homework"])+0.3*average(stu["quizzes"])+0.6*average(stu["tests"])

# function get_letter_grade
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"

第八节

1 练习：写一个函数get_class_average，参数是班级的列表，求出这个班级所有人的平均值

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(lst):
    sum = 0
    for num in lst:
        sum = sum+num
    return float(sum)/len(lst)

# function get_average
def get_average(stu):
    return 0.1*average(stu["homework"])+0.3*average(stu["quizzes"])+0.6*average(stu["tests"])

# function get_letter_grade
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"

# function get_class_average
def get_class_average(class_list):
    sum = 0
    for stu in class_list:
        sum = sum + get_average(stu)
    return float(sum)/len(class_list)
    

第十节

1 练习：打印出students这个班级列表的平均值，然后利用这个值求平均等级

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]
}

# students list
students = [lloyd , alice , tyler]

# Add your function below!
def average(lst):
    sum = 0
    for num in lst:
        sum = sum+num
    return float(sum)/len(lst)

# function get_average
def get_average(stu):
    return 0.1*average(stu["homework"])+0.3*average(stu["quizzes"])+0.6*average(stu["tests"])

# function get_letter_grade
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"

# function get_class_average
def get_class_average(class_list):
    sum = 0
    for stu in class_list:
        sum = sum + get_average(stu)
    return float(sum)/len(class_list)

# print you result
score = get_class_average(students)
print score
print get_letter_grade(score