Python编程：从入门到实践——练习题答案（第三章）

第3章 列表简介

3-1 姓名： 将一些朋友的姓名存储在一个列表中，并将其命名为 names。依次访问该列表中的每个元素，从而将每个朋友的姓名都打印出来。

names = ['xiaoming','xiaohong','xiaofang']
 
for name in names:
    print(name)

运行结果：

xiaoming
xiaohong
xiaofang

3-2 问候语： 继续使用练习 3-1 中的列表，但不打印每个朋友的姓名，而为每人打印一条消息。每条消息都包含相同的问候语，但抬头为相应朋友的姓名。

names = ['xiaoming','xiaohong','xiaofang']
 
for name in names:
    print(name + ", nice to meet you!")

运行结果：

xiaoming, nice to meet you!
xiaohong, nice to meet you!
xiaofang, nice to meet you!

3-3 自己的列表： 想想你喜欢的通勤方式，如骑摩托车或开汽车，并创建一个包含多种通勤方式的列表。根据该列表打印一系列有关这些通勤方式的宣言，如“I would like to own a Honda motorcycle”。

cars = ['BMW','Audi','Volkswagen']
 
for car in cars:
	print("I would like to own a " + car + " car!")

运行结果：

I would like to own a BMW car!
I would like to own a Audi car!
I would like to own a Volkswagen car!

3-4 嘉宾名单：如果你可以邀请任何人一起共进晚餐（无论是在世的还是故去的），你会邀请哪些人？请创建一个列表，其中包含至少 3 个你想邀请的人；然后，使用这个列表打印消息，邀请这些人来与你共进晚餐。

persons = ['Mayun','Mahuateng','Leijun']

for person in persons:
    print(person + ", I want to invite you to have dinner with me.")

运行结果：

Mayun, I want to invite you to have dinner with me.
Mahuateng, I want to invite you to have dinner with me.
Leijun, I want to invite you to have dinner with me.

3-5 修改嘉宾名单：你刚得知有位嘉宾无法赴约，因此需要另外邀请一位嘉宾。

#以完成练习 3-4 时编写的程序为基础，在程序末尾添加一条 print 语句，指出哪位嘉宾无法赴约。
print('Sorry, ' + persons[2] + " couldn't come.")

#修改嘉宾名单，将无法赴约的嘉宾的姓名替换为新邀请的嘉宾的姓名。
persons[2] = 'Liuqiangdong'

#再次打印一系列消息，向名单中的每位嘉宾发出邀请。
for person in persons:
    print(person + ", I want to invite you to have dinner with me.")

运行结果：

Sorry, Leijun couldn't come.
Mayun, I want to invite you to have dinner with me.
Mahuateng, I want to invite you to have dinner with me.
Liuqiangdong, I want to invite you to have dinner with me.

3-6 添加嘉宾：你刚找到了一个更大的餐桌，可容纳更多的嘉宾。请想想你还想邀请哪三位嘉宾。

#以完成练习 3-4 或练习 3-5 时编写的程序为基础，在程序末尾添加一条 print 语句，指出你找到了一个更大的餐桌。
print('I find a bigger table !')

#使用 insert()将一位新嘉宾添加到名单开头。
persons.insert(0,'Zhoujielun')

#使用insert()将一位新嘉宾添加到名单中间。
persons.insert(2,'Chengyixun')

#使用insert()将一位新嘉宾添加到名单末尾。
persons.append('Dengziqi')

#打印一系列消息，向名单中的每位嘉宾发出邀请。
for person in persons:
    print(person + ", I want to invite you to have dinner with me.")

运行结果：

I find a bigger table !
Zhoujielun, I want to invite you to have dinner with me.
Mayun, I want to invite you to have dinner with me.
Chengyixun, I want to invite you to have dinner with me.
Mahuateng, I want to invite you to have dinner with me.
Liuqiangdong, I want to invite you to have dinner with me.
Dengziqi, I want to invite you to have dinner with me.

3-7 缩减名单：你刚得知新购买的餐桌无法及时送达，因此只能邀请两位嘉宾。

#以完成练习 3-6 时编写的程序为基础，在程序末尾添加一行代码，打印一条你只能邀请两位嘉宾共进晚餐的消息。
print('Only two guests can be invited to dinner.')

#使用 pop()不断地删除名单中的嘉宾，直到只有两位嘉宾为止。每次从名单中弹出一位嘉宾时，都打印一条消息，让该嘉宾知悉你很抱歉，无法邀请他来共进晚餐。
while len(persons)>2:
    	print(persons.pop() + ", I can't invite you to have dinner with me.")

#对于余下的两位嘉宾中的每一位，都打印一条消息，指出他依然在受邀人之列。
for person in persons:
	print(person + ', you are still in my list.')

#使用 del 将最后两位嘉宾从名单中删除，让名单变成空的。打印该名单，核实程序结束时名单确实是空的。
del persons[0]
del persons[0]

print(persons)

运行结果：

Only two guests can be invited to dinner.
Dengziqi, I can't invite you to have dinner with me.
Liuqiangdong, I can't invite you to have dinner with me.
Mahuateng, I can't invite you to have dinner with me.
Chengyixun, I can't invite you to have dinner with me.
Zhoujielun, you are still in my list.
Mayun, you are still in my list.
[]

3-8 放眼世界：想出至少 5 个你渴望去旅游的地方。

#将这些地方存储在一个列表中，并确保其中元素不是按字母顺序排序的
city = ['Beijing','Shanghai','Chengdu','Nanjing','Xianggang']

#按原始排列顺序打印该列表
print(city)

#使用sorted()按字母顺序打印这个列表，同时不要修改它
print(sorted(city))

#再次打印该列表，核实排列顺序未改变
print(city)

#使用sorted()按字母顺序相反的顺序打印这个列表，同时不要修改它
print(sorted(city,reverse = True))

#再次打印该列表，核实排列顺序未改变
print(city)

#使用reserve()修改列表元素的排列顺序。打印该列表
city.reverse()
print(city)

#使用reserve()再次修改列表元素的排列顺序。打印该列表
#核实已经恢复到原来的排列顺序
city.reverse()
print(city)

#使用sort()按字母顺序打印这个列表
city.sort()
print(city)

#使用sort()按字母顺序相反的顺序打印这个列表
city.sort(reverse = True)
print(city)

运行结果：

['Beijing', 'Shanghai', 'Chengdu', 'Nanjing', 'Xianggang']
['Beijing', 'Chengdu', 'Nanjing', 'Shanghai', 'Xianggang']
['Beijing', 'Shanghai', 'Chengdu', 'Nanjing', 'Xianggang']
['Xianggang', 'Shanghai', 'Nanjing', 'Chengdu', 'Beijing']
['Beijing', 'Shanghai', 'Chengdu', 'Nanjing', 'Xianggang']
['Xianggang', 'Nanjing', 'Chengdu', 'Shanghai', 'Beijing']
['Beijing', 'Shanghai', 'Chengdu', 'Nanjing', 'Xianggang']
['Beijing', 'Chengdu', 'Nanjing', 'Shanghai', 'Xianggang']
['Xianggang', 'Shanghai', 'Nanjing', 'Chengdu', 'Beijing']

3-9 晚餐嘉宾：在完成练习 3-4~练习 3-7 时编写的程序之一中，使用 len()打印一条消息，指出你邀请了多少位嘉宾来与你共进晚餐。

persons = ['Mayun','Mahuateng','Leijun']

for person in persons:
    print(person + ", I want to invite you to have dinner with me.")

print('I have invited '+str(len(persons))+' persons.')

运行结果：

Mayun, I want to invite you to have dinner with me.
Mahuateng, I want to invite you to have dinner with me.
Leijun, I want to invite you to have dinner with me.
I have invited 3 persons.