Python中的字典

朴灿烈づ我的快乐病毒、 2021-07-26 01:57 385阅读 0赞

**目录**

一、字典中对属性的基本使用

获取属性值

新增属性

修改属性

删除属性

二、遍历字典：遍历所有属性、key、value

三、字典嵌套

--------------------

# 一、字典中对属性的基本使用 #

包括对属性值的获取，对属性的增加、修改以及删除

## 获取属性值 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70][]

user = {
        "username": "lijiang",
        "password": 123,
    }
    
    print(user)
    print(user["username"])
    print(user["password"])

## 新增属性 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1][]

user = {
        "username": "lijiang",
        "password": 123,
    }
    
    print(user)
    
    # 新增一个属性
    user["age"] = 22
    print(user)
    print(user["age"])

## 修改属性 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 2][]

user = {
        "username": "lijiang",
        "password": 123,
        "age": 22
    }
    
    print(user)
    
    # 修改属性值
    user["age"] = 30
    print(user)
    print(user["age"])

## 删除属性 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 3][]

user = {
        "username": "lijiang",
        "password": 123,
        "age": 22
    }
    
    print(user)
    
    # 删除属性
    del user["age"]
    print(user)

# 二、遍历字典：遍历所有属性、key、value #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 4][]

user = {
        "username": "lijiang",
        "password": 123,
    }
    
    # 遍历所有属性
    for key, val in user.items():
        print(key, "=", val)
    print("---------------------")
    
    # 遍历所有key
    for key in user.keys():
        print(key, " is ", user[key])
    print("---------------------")
    
    # 遍历所有的value
    for val in user.values():
        print(val)

# 三、字典嵌套 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 5][]

user = {
        "username": "lijiang",
        "password": 123,
        "info": {
            "age": 22,
            "nickname": "我是李疆呀哈哈哈",
    
        },
        "friends": ["A", "B", "C"]
    }
    
    print(user)
    print(user["info"])
    print(user["friends"])
    print("----------------------------")
    
    for key, val in user["info"].items():
        print(key, "=", val)
    print("----------------------------")
    
    
    for val in user["friends"]:
        print(val)

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