(字典)dictionaries的基本操作

#字典在python里是一系列的键值对，每个键对应一个值，可以通过键来访问值，这里的值可以是：数字，字符串。列表，乃至字典，
#字典放在{}花括号中的一系列键值对表示
diction = {"color" : "green","age" : 24}
print(diction["age"]) #24

#添加键值对,python你在乎添加键值对的顺序，他只在乎添加的键值对的内容
diction["x_position"] = 0
diction["y_position"] = 25
print(diction)

#修好对应键的值
diction_1 = {}
diction_1["x_position"] = 0
diction_1["y_position"] = 25
diction_1["speed"] = "medium"
if diction_1["speed"] == "slow":
    x_increment = 1
elif diction_1["speed"] == "medium":
    x_increment = 2
else:
    x_increment = 2
diction_1["x_position"] = diction_1["x_position"] + x_increment
print("现在的x的位置是：",diction_1["x_position"])

#删除键值对，使用del 语法是：del 字典名["键"],删除后的键值对就永远消失了
diction = {'x_position':12,'y_position':23}
print("删除之前：",diction)
del diction['x_position']
print("删除之后：",diction)

以上都是完成一个对象的所有信息调查，接下来可以是多个对象的调查：

#除了可以把字典写成一行，还可以写成多行
people_languages = {
    '大怪':'C',
    '小怪':'C++',
    '八戒':'Java',
    '唐生':'Python',
}

print('八戒最喜欢的语言是：'+people_languages['八戒'].title()+'.') #八戒最喜欢的语言是：Java.

#遍历字典的所有键值对
people_languages = {
    '大怪':'C',
    '小怪':'C++',
    '八戒':'Java',
    '唐生':'Python',
}
#使用到了字典的方法item(),这个方法返回的是键值对列表
for key,value in people_languages.items():
    print('KEY: '+key+'\n'+'VALUE: '+value)

people_languages = {
    '大怪':'C',
    '小怪':'C++',
    '八戒':'Java',
    '唐生':'Python',
}
for name in people_languages.keys():
    print(name)

# 大怪
# 小怪
# 八戒
# 唐生

people_languages = {
    '大怪':'C',
    '小怪':'C++',
    '八戒':'Java',
    '唐生':'Python',
}
frinedName = ['孙悟空','蜘蛛精','小怪','唐生']
for name in people_languages.keys():
    if name in frinedName:
        print('Hi '+name+',i have see you in frindName')
    else:
        continue

# Hi 小怪,i have see you in frindName
# Hi 唐生,i have see you in frindName

#按照sorted来排序打印
people_languages = {
    '大怪':'C',
    '小怪':'C++',
    '八戒':'Java',
    '唐生':'Python',
}
for name in sorted(people_languages.keys()):
    print(name,end=" ")
print()
for name in sorted(people_languages.keys(),reverse=True):
    print(name,end=" ")
# 八戒 唐生 大怪 小怪 
# 小怪 大怪 唐生 八戒

#考虑到值得重复问题
people_languages = {
    '大怪':'C',
    '小怪':'C++',
    '八戒':'Java',
    '唐生':'Python',
    '哪吒':'C++',
}

#只打印出所有的值，无论重复与否
for value in people_languages.values():
    print(value,end=" ") #C C++ Java Python C++
print()
#考虑值得重复，不打印重复的值，要用到set
for value in set(people_languages.values()):
    print(value,end=" ") #C Java C++ Python

#在列表中存放字典
aliens = []
for alien in range(0,5):
    new_alien = {'name':'bajie','age':12}
    aliens.append(new_alien)

for alien in aliens[:2] :
    if alien['name'] == 'bajie':
        alien['name'] = 'feiwu'
        alien['age'] = 19
for alien in aliens :
    print(alien)
# {'name': 'feiwu', 'age': 19}
# {'name': 'feiwu', 'age': 19}
# {'name': 'bajie', 'age': 12}
# {'name': 'bajie', 'age': 12}
# {'name': 'bajie', 'age': 12}

#在字典中添加列表
Languages_friend = {
    'xiaoming':['python','C++'],
    'xiaohua':['python','C'],
    'cuihua':'Java',
    'yuejie':['Qt','ruby'],
}
#切记这里必须是.item()，
for name,languages in Languages_friend.items():
    print("name : "+name,end="\t")
    for language in languages:
        print("language : ",language.title(),end=" ")
    print()

#在字典中存放字典
Users = {
    'xiaoming':{
        'age':24,
        'sex':'man',
        'favorite':'basketball',
        'province':'shanxi',
    },  #不要忘记这里有一个逗号
    'cuihua':{
        'age':25,
        'sex':'woman',
        'favorite':'singing',
        'province':'guangxi',
    }
}

for name,userInfo in Users.items():
    print("name : ",name)
    for key,value in userInfo.items():
        print(key," ",value)