dict = {key1 : value1, key2 : value2 }

# 創(chuàng)建字典
dict1 = {"姓名": "甜甜"}
print(type(dict1), dict1)  # <class 'dict'> {'姓名': '甜甜'}

dict2 = {
    "姓名": "甜甜",
    "性別":  "女",
    "年齡": "19"
}
print(dict2)  # {'姓名': '甜甜', '性別': '女', '年齡': '19'}

# 使用dict 創(chuàng)建對(duì)象，鍵不可以加""引號(hào)
dict1 = dict(姓名="甜甜", 性別="女", 年齡="19")
print(type(dict1), dict1)  # <class 'dict'> {'姓名': '甜甜', '性別': '女', '年齡': '19'}

list1 = ["姓名", "性別", "年齡"]
list2 = ["甜甜", "女", "19"]
# zip()函數(shù)將對(duì)象中對(duì)應(yīng)的元素打包成一個(gè)個(gè)元組，返回由這些元組組成的對(duì)象
dict2 = dict(zip(list1, list2))
print(dict2)  # {'姓名': '甜甜', '性別': '女', '年齡': '19'}


# 使用生成列創(chuàng)建字典
dict3 = {x: x ** 3 for x in range(6)}
print(dict3)  # {0: 0, 1: 1, 2: 8, 3: 27, 4: 64, 5: 125}

dict1 = {'姓名': '甜甜', '性別': '女', '年齡': '19'}
print(len(dict1))  # 3

for ch in dict1:
    print(ch)
'''
姓名
性別
年齡
'''

dict1 = {'姓名': '甜甜', '性別': '女', '年齡': '19'}

# 成員運(yùn)算
print("姓名" in dict1, "性別" not in dict1)  # True False

# 先判斷在修改
if "姓名" in dict1:
    dict1["姓名"] = '王甜甜'
    print(dict1)  # {'姓名': '王甜甜', '性別': '女', '年齡': '19'}

# 通過索引為dict1 增加數(shù)據(jù)
dict1["愛好"] = "旅游"

print("愛好" in dict1)  # True


# 對(duì)字典的鍵進(jìn)行循環(huán)并通索引運(yùn)算獲取鍵對(duì)應(yīng)的值
for key in dict1:
    print(f'{key}: {dict1[key]}')
'''
姓名: 王甜甜
性別: 女
年齡: 19
愛好: 旅游
'''

# 字典的嵌套
students = {
    10001: {"name": "小明", "sex": "男", "age": 18},
    10002: {"name": "小紅", "sex": "女", "age": 16},
    10003: {"name": "小白", "sex": "女", "age": 19},
    10004: {"name": "小周", "sex": "男", "age": 20}
}

# 使用get方法通過鍵獲取對(duì)應(yīng)的值，如果取不到是返回的默認(rèn)值（默認(rèn)為None）
print(students.get(10002))    # {'name': '小紅', 'sex': '女', 'age': 16}
print(students.get(10005))    # None
print(students.get(10005, "沒有這個(gè)學(xué)生"))    # 沒有這個(gè)學(xué)生

# 獲取字典中所有的鍵
print(students.keys())      # dict_keys([10001, 10002, 10003, 10004])
# 獲取字典中所有的值
print(students.values())    # dict_values([{...}, {...}, {...}, {...}])
# 獲取字典中所有的鍵值對(duì)
# dict_items([(10001, {...}), (10002, {....}), (10003, {...}), (10004, {...})])
print(students.items())
# 對(duì)字典中所有的鍵值對(duì)進(jìn)行循環(huán)遍歷
for key, value in students.items():
    print(key, '--->', value)

# 使用pop方法通過鍵刪除對(duì)應(yīng)的鍵值對(duì)并返回該值
stu1 = students.pop(10002)
print(stu1)             # {'name': '小紅', 'sex': '女', 'age': 16}
print(len(students))    # 3
# 如果刪除的不在字典中，會(huì)引發(fā)KeyError異常
# stu2 = students.pop(10005)    # KeyError: 10005


# 使用popitem方法刪除字典中最后一組鍵值對(duì)并返回對(duì)應(yīng)的二元組
# 如果字典中沒有元素，調(diào)用該方法將引發(fā)KeyError異常
key, value = students.popitem()
print(key, value)    # 10004 {'name': '小周', 'sex': '男', 'age': 20}

# setdefault可以更新字典中的鍵對(duì)應(yīng)的值或向字典中存入新的鍵值對(duì)
# setdefault方法的第一個(gè)參數(shù)是鍵，第二個(gè)參數(shù)是鍵對(duì)應(yīng)的值
# 如果這個(gè)鍵在字典中存在，更新這個(gè)鍵之后會(huì)返回原來與這個(gè)鍵對(duì)應(yīng)的值
# 如果這個(gè)鍵在字典中不存在，方法將返回第二個(gè)參數(shù)的值，默認(rèn)為None
result = students.setdefault(10005, {"name": "小綠", "sex": "女", "age": 18})
print(result)        # {'name': '小綠', 'sex': '女', 'age': 18}
print(students)      # {10001: {...}, (10003, {...}), 10005: {...}}

# 使用update更新字典元素，相同的鍵會(huì)用新值覆蓋掉舊值，不同的鍵會(huì)添加到字典中
others = {
    10005: {"name": "小南", "sex": "男", "age": 19},
    10006: {"name": "小北", "sex": "男", "age": 19},
    10007: {"name": "小冬", "sex": "男", "age": 19}
}
students.update(others)
# {10001: {...}, 10003: {...}, 10005: {...}, 10006: {...}, 10007: {...}}
print(students)