时间:2021-07-01 10:21:17 帮助过:53人阅读
# 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)
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