Guibs 的 Python学习_字典

# 字典# Python 中字典是一系列键值对.
# 键和值之间用 : 分隔, 键-值对之间用 , 
分隔book_0 = {'name': 'Swift', 'price': 22}
book_1 = {'name': 'Python', 'price': 22}
# 访问字典中的值# 字典中的所有键print(book_0.keys()
)# 字典中的所有值print(book_0.values())
# 要获取与键相关联的值, 可以依次指定字典名和放在方括号内的键
print(book_0['name'] + ': ' + str(book_0['price']))
print(book_1['name'] + ": " + str(book_1['price']))
# 创建一个空字典book_2 = {}
print(book_2)
# 添加键值对
# 要添加键-值对, 可依次指定字典名、用方括号括起来的键和关联的值
book_2['author'] = 'Gubis'print(book_2)
# 修改字典中的值# 依次指定字典名、用方括号括起来的键和更新的值book_2['author'] = "Guibs82"print(book_2)
# 删除键值对# [del]del book_2['author']
print(book_2)
# 遍历字典
# [dictionary.items()]user_0 = {    'username': 'efermi',    'first': 'enrico',    'last': 'fermi',
}for key, value in user_0.items():
    print("Key: " + key)
    print("Value: " + value)# 遍历字典中所有的键# [.keys()]for key in user_0.keys():
    print("With .keys() " + key + " and value is " + user_0[key])for key in user_0:
    print("Without .keys() " + key + " and value is " + user_0[key])# 按顺序遍历字典中的所有键# [sorted()]for key in sorted(user_0.keys()):
    print("Sorted key is " + key)# 遍历字典中所有的值for value in user_0.values():
    print(value)# 若字典中含有大量重复的值, 为了剔除重复值, 可以使用集合 set# [set()]favorite_languages = {    'Guibs': 'Swift_and_Python',    
'Guibs82': 'Swift_and_Python',    'Someone': 'Python'}for value in favorite_languages.values():
    print("Without set() value is " + value)for value in set(favorite_languages.values()):
    print("With set() value is " + value)# 嵌套# 字典、列表可以相互嵌套# 列表中存储字典books = [book_0, book_1, book_2]for book in books[:1]:
    print(book)# 字典中存储列表pizza = {    'name': 'B_Pizza',    'size': ['small', 'big'],    'price': [10, 15],
}
print(pizza)# 字典中存储字典price = {    'small': 20,    'big': 25,
}
pizza = {    'name': 'G_Pizza',    'size': ['small', 'big'],    'price': price
}
print(pizza)