python字典

4. 字典
   字典是一个无序、可变和有索引的集合。

#创建字典
dict1={"brand":"peak","model":"123","year":"2023"}
print(dict1)
#取moudel的值
x=dict1["model"]
x=dict1.get("model")
#遍历dict1
for x in dict1:
	print(x)
	print(dict1[x])
#遍历dict中values的值
for x in dict1.values():
	print(x)
#用items（）函数遍历键和值
for x,y in dict1.items():
	print(x:y)
#字典中的项目数
print(len(dict1))
#查找
dict1={"brand":"peak","model":"123","year":"2023"}
if "model" in dict1:
  print("yes")
#增加
dict1={"brand":"peak","model":"123","year":"2023"}
dict1["color"]="blue"
print(dict1)
#删除
del dict1["color"]
print(dict1)
del dict1
print(dict1)	#将会报错，dict1已经被删除
#复制
dict2=dict1.copy()
print(dict2)