python字典

# 字典
# dict
# dic = {
#     "k1": ‘v1‘,
#     "k2": ‘v2‘
# }
# 1 根据序列，创建字典，并指定统一的值
# v = dict.fromkeys(["k1",123,"999"],123)
# print(v)

# 2 根据Key获取值，key不存在时，可以指定默认值（None）
# v = dic[‘k22222‘]
# print(v)
# v = dic.get(‘k1‘,222221)
# print(v)

# 3 删除并获取值
# dic = {
#     "k1": ‘v1‘,
#     "k2": ‘v2‘
# }
# v = dic.pop(‘k1‘,90)
# print(dic,v)
# k,v = dic.popitem()
# print(dic,k,v)

# 4 设置值，
# 已存在，不设置，获取当前key对应的值
# 不存在，设置，获取当前key对应的值
# dic = {
#     "k1": ‘v1‘,
#     "k2": ‘v2‘
# }
# v = dic.setdefault(‘k1111‘,‘123‘)
# print(dic,v)

# 5 更新
# dic = {
#     "k1": ‘v1‘,
#     "k2": ‘v2‘
# }
# dic.update({‘k1‘: ‘222221‘,‘k3‘: 123})
# print(dic)
# dic.update(k1=123,k3=345,k5="asdf")
# print(dic)

# 6 keys()  7 values()   8 items()   get   update
##################################################
# 1.基本机构
# info = {
#     "k1": "v1",# 键值对
#     "k2": "v2"
# }
# 2.字典的value可以是任何值
# info = {
#     "k1": 18,
#     "k2": True,
#     "k3": [
#         11,
#         [],
#         (),
#         22,
#         33,
#         {
#             ‘kk1‘: ‘vv1‘,
#             ‘kk2‘: ‘vv2‘,
#             ‘kk3‘: (11,22),
#         }
#     ],
#     "k4": (11,22,33,44)
# }
# print(info)

# 3.布尔值(1,0)、列表、字典不能作为字典的key
# info ={
#     1: ‘asdf‘,
#     "k1": ‘asdf‘,
#     True: "123",
#     # [11,22]: 123
#     (11,22): 123,
#     # {‘k1‘:‘v1‘}: 123
#
# }
# print(info)

# 4.字典无序
# info = {
#     "k1": 18,44)
# }
# print(info)

# 5.索引方式找到指定元素
# info = {
#     "k1": 18,
#     2: True,44)
# }
# # v = info[‘k1‘]
# # print(v)
# # v = info[2]
# # print(v)
# v = info[‘k3‘][5][‘kk3‘][0]
# print(v)

# 6.字典支持 del 删除
# info = {
#     "k1": 18,44)
# }

# del info[‘k1‘]
#
# del info[‘k3‘][5][‘kk1‘]
# print(info)

# 7.for循环
# info = {
#     "k1": 18,44)
# }

# for item in info:
#     print(item)
#
# for item in info.keys():
#     print(item)

# for item in info.values():
#     print(item)

# for item in info.keys():
#     print(item,info[item])

# for k,v in info.items():
#     print(k,v)

# True 1  False 0
# info ={
#     "k1": ‘asdf‘,
#     # {‘k1‘:‘ v1‘}: 123
#
# }
# print(info)