python-字典基础

# 字典 dict

# 初始化 {dict} form_key

# dict1 = {}

# dict2 = {1: 'a', 2: "b", 3: "c"}

#

# print(dict2[2])

# 添加  obj[key]=value  setdefault

# dict1 = {}

# dict2 = {1: 'a', 2: "b", 3: "c"}

# dict1["a"]=1

# print(dict1)

# dict1.setdefault("b",2)

# print(dict1)

# dict1.setdefault("b",2)

# print(dict1)

# 取值

# dict1 = {}

# dict2 = {1: 'a', 2: "b", 3: "c"}

# print(dict2[2])

# print(dict2.keys())

# print(dict2.values())

# print(dict2.items())

# print(dict2.get(2))

# for key,value in enumerate(dict2):

#    print(key,value)

# 取索引

# dict1 = {}

# dict2 = {1: 'a', 2: "b", 3: "c"}

# print(dict2[3])

# 取索引和值 items()

# dict1 = {}

# dict2 = {1: 'a', 2: "b", 3: "c"}

# print(dict2.items())

# for key,value in dict2.items():

#    print(key,value)

# 取长度 len()

# dict1 = {}

# dict2 = {1: 'a', 2: "b", 3: "c"}

# print(len(dict2))

# 删除  pop  del

# dict1 = {}

# dict2 = {1: 'a', 2: "b", 3: "c"}

# a = dict2.pop(3)

# print(a)

# print(dict2)

# del dict2[3]

# print(dict2)

#拼接 update

dict1 = {4:"d"}

dict2 = {1:'a',2:"b",3:"c"}

dict2.update(dict1)

print(dict2)