字典的基本操作及循環

stu_name = {'libo':'85','lihuiting':'90','liguobing':'80'}#定義一個字典 key-value形式存儲的

print(stu_name)
#曾
stu_name['xiaohong'] = '95'#增加一個元素
stu_name.setdefault('xiaobei','77')#增加一個元素
print(stu_name)#從打印的結果來看字典是無序的

#修改
stu_name['libo']='90' #把libo的value改成90
print(stu_name)

#刪除一個值
stu_name.pop('xiaohong')#指定一個key來進行刪除
print(stu_name)
stu_name.popitem()#隨機刪除一個值
print(stu_name)
del stu_name['libo']#指定一個key來進行刪除
print(stu_name)
stu_name.clear()
print(stu_name)#清除一個字典

#查看一個值
stu_name = {'libo':'85','lihuiting':'90','liguobing':'80'}
print(stu_name.keys())#獲取字典的所有的key
print(stu_name.values())#獲取字典的所有value
print(stu_name.items())#獲取字典所有的key-value

print(stu_name.get('phone'))#取不到這個key的話，就是None
print(stu_name.get('phone',110))#如果取不到這個key的話，默認就是110
print(stu_name['phone'])#如果key不存在會報錯

#循環字典
for i in stu_name: #直接循環只是循環的key
 print(i)
for k, v in stu_name.items():#循環字段中的key-value
 print(k,v)

#字典的嵌套循環

name = {'libo':'90','test':'100','xunhuan':{'test11':'99','test222':'88'}}

for k,v in name.items():
 if type(v)== dict:
 for i in v:
 print(i)
 print(k,v)