python字典详解

python字典详解

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1.字典

请用python中的数据类型表示’迪迦奥特曼’

name = '迪迦奥特曼'
age = 18
gender = 'man'
height = 250

info = {"name":"迪迦奥特曼"，"age":18,"gender":"man","height":250}#4个键值对表示了迪迦奥特曼所有属性

帮助用户去表示一个事物的所有信息(事物是有多个属性的)

基本格式：

dict = {键:值，键:值，键:值，键:值，键:值，键:值}

2.字典功能

info = {"name":"迪迦奥特曼"，"age":18,"gender":"man","height":250}

• keys,获取字典中所有的键
• values，获取字典中所有的值
• items，获取字典中所有的键值对

info = {"name":"迪迦奥特曼","age":18,"gender":"man","height":250}
for i in info.keys():
    print(i)
print("*********************************")
for i in info.values():
    print(i)
print("*********************************")
for key,value in info.items():
    print(key,value)

• 通用功能

  • len

    info = {"name":"迪迦奥特曼","age":18,"gender":"man","height":250}
    print(len(info))
    

  • 索引

    info = {"name":"迪迦奥特曼","age":18,"gender":"man","height":250}
    info["name"]
    info["age"]  #得到对应键的值
    

  • for循环

    info = {"name":"迪迦奥特曼","age":18,"gender":"man","height":250}
    for item in info:
        print(item)
    #结果："name","age","gender","height"
    #如果直接for循环一个字典相当于循环其keys()
    

  • 修改(存在就修改/不存在就添加)

    #改值
    info = {"name":"迪迦奥特曼","age":18,"gender":"man","height":250}
    info["age"] = 19
    print(info)
    #改键
    #删除后再增加
    

  • 删除

    info = {"name":"迪迦奥特曼","age":18,"gender":"man","height":250}
    del info['name']  #键值对是成对的删除其键，值也会被删除
    

注意：

字典中值可以由python中的任意数据类型组成，但是键只能由可哈希数据类型组成即不可变数据类型如：数值，字符串，元组，布尔类型组成。