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 dictionarieslloyd = {"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 herestudents = [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 herestudents = [lloyd , alice , tyler]# you code hrrefor 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_averagedef 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_averagedef get_average(stu):    return 0.1*average(stu["homework"])+0.3*average(stu["quizzes"])+0.6*average(stu["tests"])# function get_letter_gradedef 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_averagedef get_average(stu):    return 0.1*average(stu["homework"])+0.3*average(stu["quizzes"])+0.6*average(stu["tests"])# function get_letter_gradedef 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_averagedef 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 liststudents = [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_averagedef get_average(stu):    return 0.1*average(stu["homework"])+0.3*average(stu["quizzes"])+0.6*average(stu["tests"])# function get_letter_gradedef 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_averagedef 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 resultscore = get_class_average(students)print scoreprint get_letter_grade(score