字典嵌套
含义：将一系列字典存储在列表中，或将列表作为值存储在字典中
在列表中嵌套字典、在字典中嵌套列表、在字典中嵌套字典
字典列表
创建多个字典，将字典存放在列表中
使用range()自动生成多个字典
使用for循环及if语句修改创建的多个字典
# 案例1：字典嵌套在列表中，打印列表
alien_0 = {'color': 'green','points': 5}
alien_1 = {'color': 'yellow','points': 10}
alien_2 = {'color': 'red','points': 15}
aliens = [alien_0,alien_1,alien_2]
for alien in aliens:
print(alien)
{'color': 'green', 'points': 5}
{'color': 'yellow', 'points': 10}
{'color': 'red', 'points': 15}
# 案例2： 使用range()自动创建多个字典,最后存放到列表中
# 创建一个用于存储的空列表
aliens = []
# 创建30个具体的字典
for alien in range(30):
new_alien = {'color': 'green','points': '5','speed': 'slow'}
aliens.append(new_alien)
# 显示前五个字典
for alien in aliens[:5]:
print(alien)
print(".....")
# 显示创建了多少个字典
print("Total number of aliens: " + str(len(aliens)))
{'color': 'green', 'points': '5', 'speed': 'slow'}
{'color': 'green', 'points': '5', 'speed': 'slow'}
{'color': 'green', 'points': '5', 'speed': 'slow'}
{'color': 'green', 'points': '5', 'speed': 'slow'}
{'color': 'green', 'points': '5', 'speed': 'slow'}
.....
Total number of aliens: 30
# 案例3：修改其中创建的字典
# 创建一个用于存储的空列表
aliens = []
# 创建30个具体的字典
for alien_number in range(0,30):
new_alien = {'color': 'green','points': '5','speed': 'slow'}
aliens.append(new_alien)
# 修改前3个字典
for alien in aliens[0:3]:
if alien['color'] == 'green':
alien['color'] = 'yellow'
alien['points'] = 10
alien['speed'] = 'medium'
# 显示前5个字典
for alien in aliens[:5]:
print(alien)
print(".....")
{'color': 'yellow', 'points': 10, 'speed': 'medium'}
{'color': 'yellow', 'points': 10, 'speed': 'medium'}
{'color': 'yellow', 'points': 10, 'speed': 'medium'}
{'color': 'green', 'points': '5', 'speed': 'slow'}
{'color': 'green', 'points': '5', 'speed': 'slow'}
.....
在字典中存储列表
将列表存储到字典中
使用字典名和键来访问值
列表和字典的嵌套层次不应该太多
# 案例1：
# 存储所点比萨的信息
pizza = {
'curst' : 'thick',
'toppings': ['mushrooms','extra cheese'],
}
# 概述所点的比萨
print("You ordered a " + pizza['curst'] + "-crust pizza" +
" with the following toppings:")
for topping in pizza['toppings']:
print("\t" + topping)
You ordered a thick-crust pizza with the following toppings:
mushrooms
extra cheese
# 案例2：
# 字典中嵌套列表，用两个for循环，第一个for循环遍历字典，第二个for循环遍历列表
favorite_languages = {
'jen': ['python','ruby'],
'sarah': ['c'],
'edward': ['ruby','go'],
'phil': ['python','haskell'],
}
# 遍历字典
for name,languages in favorite_languages.items():
#判断字典的值有几个
if len(languages) > 1:
print("\n" + name.title() + " 's favorite language are:")
# 字典的值是列表时，for循环遍历列表
for language in languages:
print("\t" + language.title())
else:
print("\n" + name.title() + " 's favorite language is:")
print("\t" + languages[0].title())
Jen 's favorite language are:
Python
Ruby
Sarah 's favorite language is:
C
Edward 's favorite language are:
Ruby
Go
Phil 's favorite language are:
Python
Haskell
在字典中存储字典
# 首先定义了一个名为 users 的字典，其中包含两个键：用户名 'aeinstein' 和 'mcurie' ；
# 与每个键相关联的值都是一个字典，其中包含用户的名、姓和居住地，我们遍历字典 users ，
# 让 Python 依次将每个键存储在变量 username 中，并依次将与当前键相关联的字典存储在变量
# user_info 中。在主循环内部，我们将用户名打印出来。
# 我们开始访问内部的字典。变量 user_info 包含用户信息字典，而该字典包含三个键：
# 'first' 、 'last' 和 'location' ；对于每位用户，我们都使用这些键来
# 生成整洁的姓名和居住地，然后打印有关用户的简要信息
users = {
'asinstein': {
'first': 'albert',
'last': 'einstein',
'location': 'princeton',
},
'mcurie': {
'first': 'marie',
'last': 'curie',
'location': 'paris',
},
}
for username,user_info in users.items():
print("\nUsername: " + username.title())
full_name = user_info['first'] + " " + user_info['last']
location = user_info['location']
print("\tFull name: " + full_name.title())
print("\tLocation: " + location.title())
Username: Asinstein
Full name: Albert Einstein
Location: Princeton
Username: Mcurie
Full name: Marie Curie
Location: Paris
练习
# 1.人
#使用一个字典来存储一个熟人的信息，包括名、姓、年龄和居住的城市。
#该字典应包含键 first_name 、 last_name 、 age 和 city 。将存储在该字典中
#的每项信息都打印出来。
#创建两个表示人的字典，然后将这三个字典都存储在一个名为 people 的列表中。遍历这个列表
#将其中每个人的所有信息都打印出来
people1 = {
'first_name': 'li',
'last_name': 'si',
'age': '23',
'city': 'Beijing'
}
people2 = {
'first_name': 'zhang',
'last_name': 'san',
'age': '24',
'city': 'dalian'
}
people3 = {
'first_name': 'wang',
'last_name': 'badan',
'age': '20',
'city': 'shanghai'
}
peoples = [people1,people2,people3]
for people in peoples:
name = people['first_name'].title() + " " + people['last_name'].title()
age = str(people['age'])
city = people['city'].title()
print(name + ", of " + city + ",is " + age + " years old.")
Li Si, of Beijing,is 23 years old.
Zhang San, of Dalian,is 24 years old.
Wang Badan, of Shanghai,is 20 years old.
# 2.宠物
#创建多个字典，对于每个字典，都使用一个宠物的名称来给它命名；在每个字典中，
#包含宠物的类型及其主人的名字。将这些字典存储在一个名为 pets
#的列表中，再遍历该列表，并将宠物的所有信息都打印出来
# Make an empty list to store the pets in.
pets = []
# Make individual pets, and store each one in the list.
pet = {
'animal type': 'python',
'name': 'john',
'owner': 'guido',
'weight': 43,
'eats': 'bugs',
}
pets.append(pet)
pet = {
'animal type': 'chicken',
'name': 'clarence',
'owner': 'tiffany',
'weight': 2,
'eats': 'seeds',
}
pets.append(pet)
pet = {
'animal type': 'dog',
'name': 'peso',
'owner': 'eric',
'weight': 37,
'eats': 'shoes',
}
pets.append(pet)
# Display information about each pet.
for pet in pets:
print("\nHere's what I know about " + pet['name'].title() + ":")
for key, value in pet.items():
print("\t" + key + ": " + str(value))
Here's what I know about John:
animal type: python
name: john
owner: guido
weight: 43
eats: bugs
Here's what I know about Clarence:
animal type: chicken
name: clarence
owner: tiffany
weight: 2
eats: seeds
Here's what I know about Peso:
animal type: dog
name: peso
owner: eric
weight: 37
eats: shoes
# 3.喜欢的地方：
# 创建一个名为 favorite_places 的字典。在这个字典中，将三个人的名字用作键；对于其中的每个人，
# 都存储他喜欢的 1~3 个地方。为让这个练习更有趣些，可让一些朋友指出他们喜欢的几个地方。
# 遍历这个字典，并将其中每个人的名字及其喜欢的地方打印出来
favorite_places = {
'eric': ['bear mountain', 'death valley', 'tierra del fuego'],
'erin': ['hawaii', 'iceland'],
'ever': ['mt. verstovia', 'the playground', 'south carolina']
}
for name, places in favorite_places.items():
print("\n" + name.title() + " likes the following places:")
for place in places:
print("- " + place.title())
Eric likes the following places:
- Bear Mountain
- Death Valley
- Tierra Del Fuego
Erin likes the following places:
- Hawaii
- Iceland
Ever likes the following places:
- Mt. Verstovia
- The Playground
- South Carolina
# 4.喜欢的数字
# 使用一个字典来存储一些人喜欢的数字。请想出 5 个人的名字，并将这些名字用作字典中的键；
# 想出每个人喜欢的一个数字，并将这些数字作为值存储在字典中。打印每个人的名字和喜欢
# 的数字。为让这个程序更有趣，通过询问朋友确保数据是真实的。
# 让每个人都可以有多个喜欢的数字，然后将每个人的名字及其喜欢的数字打印出来
favorite_numbers = {
'mandy': [42, 17],
'micah': [42, 39, 56],
'gus': [7, 12],
}
for name, numbers in favorite_numbers.items():
print("\n" + name.title() + " likes the following numbers:")
for number in numbers:
print(" " + str(number))
Mandy likes the following numbers:
42
17
Micah likes the following numbers:
42
39
56
Gus likes the following numbers:
7
12
# 5.喜欢的城市
# 创建一个名为 cities 的字典，其中将三个城市名用作键；对于每座城市，都创建一个字典，
# 并在其中包含该城市所属的国家、人口约数以及一个有关该城市的事实。
# 在表示每座城市的字典中，应包含 country 、 population 和 fact 等键。
# 将每座城市的名字以及有关它们的信息都打印出来
cities = {
'santiago': {
'country': 'chile',
'population': 6158080,
'nearby mountains': 'andes',
},
'talkeetna': {
'country': 'alaska',
'population': 876,
'nearby mountains': 'alaska range',
},
'kathmandu': {
'country': 'nepal',
'population': 1003285,
'nearby mountains': 'himilaya',
}
}
for city, city_info in cities.items():
country = city_info['country'].title()
population = city_info['population']
mountains = city_info['nearby mountains'].title()
print("\n" + city.title() + " is in " + country + ".")
print(" It has a population of about " + str(population) + ".")
print(" The " + mountains + " mountains are nearby.")
Santiago is in Chile.
It has a population of about 6158080.
The Andes mountains are nearby.
Talkeetna is in Alaska.
It has a population of about 876.
The Alaska Range mountains are nearby.
Kathmandu is in Nepal.
It has a population of about 1003285.
The Himilaya mountains are nearby.
