# _*_ coding:utf-8 _*_
##########字典############
#一个简单的字典
alien_0 = {'color': 'green', 'points': 5}
print(alien_0['color'])
print(alien_0['points'])
new_points = alien_0['points']
print("You just earned " + str(new_points) + " points!")
-------------------------------------------
green
5
You just earned 5 points!
-------------------------------------------
#添加键-值对
alien_0 = {'color': 'green', 'points': 5}
print(alien_0)
alien_0['x_position'] = 0
alien_0['y_position'] = 25
print(alien_0)
-------------------------------------------
{'color': 'green', 'points': 5}
{'color': 'green', 'points': 5, 'x_position': 0, 'y_position': 25}
-------------------------------------------
#先创建一个空字典
alien_0 = {}
alien_0['color'] = 'green'
alien_0['points'] = 5
print(alien_0)
-------------------------------------------
{'color': 'green', 'points': 5}
-------------------------------------------
#修改字典中的值
alien_0 = {'color': 'green', 'points': 5}
print("The alien is " + alien_0['color'] + ".")
alien_0['color'] = 'yellow'
print("The alien is now " + alien_0['color'] + ".")
-------------------------------------------
The alien is green.
The alien is now yellow.
-------------------------------------------
#一个例子：对一个能够以不同速度移动的外星人的位置进行追踪
alien_0 = {'x_position': 0, 'y_position': 25, 'speed': 'medium'}
print("Original x-position: " + str(alien_0['x_position']))
#向右移动的外星人
#据外星人当前速度决定将其移动多远
if alien_0['speed'] == 'slow':
x_increment = 1
elif alien_0['speed'] == 'medium':
x_increment = 2
else:
x_increment = 3
#新位置等于老位置加上增量
alien_0['x_position'] = alien_0['x_position'] + x_increment
print("New x-position: " + str(alien_0['x_position']))
-------------------------------------------
Original x-position: 0
New x-position: 2
-------------------------------------------
#删除键-值对
alien_0 = {'color': 'green', 'points': 5}
print(alien_0)
del alien_0['points']
print(alien_0)
-------------------------------------------
{'color': 'green', 'points': 5}
{'color': 'green'}
-------------------------------------------
#遍历字典
user_0 = {
'username': 'efermi',
'first': 'enrico',
'last': 'fermi',
}
for key, value in user_0.items():
print(" Key: " + key)
print("Value: " + value)
-------------------------------------------
Key: username
Value: efermi
Key: first
Value: enrico
Key: last
Value: fermi
-------------------------------------------
#遍历字典中的所有键
favorite_languages = {
'jen': 'Python',
'sarah': 'C',
'edward': 'Ruby',
'phil': 'Python',
}
for name in favorite_languages.keys():
print(name.title())
-------------------------------------------
Jen
Sarah
Edward
Phil
-------------------------------------------
#遍历字典时，会默认遍历所有的键
for name in favorite_languages:
print(name.title())
-------------------------------------------
Jen
Sarah
Edward
Phil
-------------------------------------------
#可以用当前键来访问与之相关联的值
favorite_languages = {
'jen': 'Python',
'sarah': 'C',
'edward': 'Ruby',
'phil': 'Python',
}
friends = ['phil', 'sarah']
for name in favorite_languages.keys():
print(name.title())
if name in friends:
print(" Hi " + name.title() + ",I see your favorite language is " + favorite_languages[name].title() + "!")
-------------------------------------------
Jen
Sarah
Hi Sarah,I see your favorite language is C!
Edward
Phil
Hi Phil,I see your favorite language is Python!
-------------------------------------------
#方法keys()并非只能用于遍历；它返回一个列表
if 'erin' not in favorite_languages.keys():
print("Erin, please take our poll!")
-------------------------------------------
Erin, please take our poll!
-------------------------------------------
#按顺序遍历字典中的所有键
favorite_languages = {
'jen': 'Python',
'sarah': 'C',
'edward': 'Ruby',
'phil': 'Python',
}
for name in sorted(favorite_languages.keys()):
print(name.title() + ", thank you for taking the poll.")
-------------------------------------------
Edward, thank you for taking the poll.
Jen, thank you for taking the poll.
Phil, thank you for taking the poll.
Sarah, thank you for taking the poll.
-------------------------------------------
#遍历字典中所有值
favorite_languages = {
'jen': 'Python',
'sarah': 'C',
'edward': 'Ruby',
'phil': 'Python',
}
print("The following languages have been mentioned:")
for language in favorite_languages.values():
print(language.title())
-------------------------------------------
The following languages have been mentioned:
Python
C
Ruby
Python
-------------------------------------------
#为剔除重复项，可使用集合（set）
print("The following languages have been mentioned:")
for language in set(favorite_languages.values()):
print(language.title())
-------------------------------------------
The following languages have been mentioned:
Python
Ruby
C
-------------------------------------------
#嵌套
#字典列表
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}
-------------------------------------------
#使用range()生成了30个外星人
#创建一个用于存储外星人的空列表
aliens = []
#创建30个绿色的外星人
for alien_number in range(30):
new_alien = {'color': 'green', 'points': 5, 'speed': 'slow'}
aliens.append(new_alien)
#显示前5个外星人
for alien in aliens[:5]:
print(alien)
print("...")
#显示创建了多少个外星人
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
-------------------------------------------
#使用for循环和if语句来修改某些外星人的颜色
#创建一个用于存储外星人的空列表
aliens = []
#创建30个绿色的外星人
for alien_number in range(30):
new_alien = {'color': 'green', 'points': 5, 'speed': 'slow'}
aliens.append(new_alien)
for alien in aliens:
if alien['color'] == 'green':
alien['color'] = 'yellow'
alien['speed'] = 'medium'
alien['points'] = 10
elif alien['color'] == 'yellow':
alien['color'] = 'red'
alien['speed'] = 'fast'
alien['points'] = 15
#显示前5个外星人
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': 'yellow', 'points': 10, 'speed': 'medium'}
{'color': 'yellow', 'points': 10, 'speed': 'medium'}
...
-------------------------------------------
#在字典中存储列表
#存储所点披萨的信息
pizza = {
'crust': 'thick',
'toppings': ['mushrooms', 'extra cheese'],
}
#概述所点的披萨
print("You ordered a " + pizza['crust'] + "-crust pizza " + "with the following toppings:")
for topping in pizza['toppings']:
print(" " + topping)
-------------------------------------------
You ordered a thick-crust pizza with the following toppings:
mushrooms
extra cheese
-------------------------------------------
#每当需要在字典中将一个键关联到多个值时，都可以在字典中嵌套一个列表
favorite_languages = {
'jen': ['Python','Ruby'],
'sarah': ['C'],
'edward': ['Ruby', 'Go'],
'phil': ['Python', 'Haskell'],
}
for name, languages in favorite_languages.items():
print(' ' + name.title() + "'s favorite languages are:")
for language in languages:
print(" " + language.title())
-------------------------------------------
Jen's favorite languages are:
Python
Ruby
Sarah's favorite languages are:
C
Edward's favorite languages are:
Ruby
Go
Phil's favorite languages are:
Python
Haskell
-------------------------------------------
#在字典中存储字典
users = {
'aeinstein': {
'first': 'albert',
'last': 'einstein',
'location': 'princeton',
},
'mcurie': {
'first': 'marie',
'last': 'curie',
'location': 'paris',
},
}
for username, user_info in users.items():
print(" Username: " + username)
full_name = user_info['first'] + " " + user_info['last']
location = user_info['location']
print(" Full name: " + full_name.title())
print(" Location: " + location.title())
-------------------------------------------
Username: aeinstein
Full name: Albert Einstein
Location: Princeton
Username: mcurie
Full name: Marie Curie
Location: Paris
-------------------------------------------
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