数据结构之字典

字典常用方法

字典的表示方法：

info_dic={'name':'haiyna','age':18,'sex':'female'}
# 常用操作：
#
1.存/取
info_dic={'name':'egon','age':18,'sex':'male'}
  print(info_dic['name11111111'])#找不到则报错了
  print(info_dic.get('name',None))
  print(info_dic.get('name222222',None))#get方法找不到不报错，可以自己设定默认值

#pop：key存在则弹出值，不存在则返回默认值，如果没有默认值则报错
# print(info_dic.pop('nam123123123123123123e',None))
# print(info_dic)

# print(info_dic.popitem())
# print(info_dic)

# info_dic['level']=10
# print(info_dic)

#
# 　　　　删除
info_dic={'name':'egon','age':18,'sex':'male'}
# info_dic.pop()
# info_dic.popitem()

# del info_dic['name']


#
# 　　　　键s，值s，键值对
info_dic={'name':'egon','age':18,'sex':'male'}
# print(info_dic.keys())
# print(info_dic.values())
# print(info_dic.items())

# for k in info_dic:
#     # print(k,info_dic[k])
#     print(k)

# print('========>')
# for k in info_dic.keys():
#     print(k)

# for val in info_dic.values():
#     print(val)

# for k,v in info_dic.items(): #k,v=('name', 'egon')
#     print(k,v)



# 　　　　长度
# info_dic={'name':'egon','age':18,'sex':'male'}
# print(len(info_dic))
#
# 　　　　循环
#
# 　　　　包含in

# info_dic={'name':'egon','age':18,'sex':'male'}
# print('name' in info_dic)
# print('name' in info_dic.keys())
# print('egon' in info_dic.values())
# print(('name','egon') in info_dic.items())



#掌握
info_dic={'name':'egon','age':18,'sex':'male'}
# info_dic.update({'a':1,'name':'Egon'})
# print(info_dic)

# info_dic['hobbies']=[]
# info_dic['hobbies'].append('study')
# info_dic['hobbies'].append('read')
# print(info_dic)

#setdefault:key不存在则设置默认值，并且放回值默认值
#key存在则不设置默认，并且返回已经有的值

# info_dic.setdefault('hobbies',[1,2])
# print(info_dic)
# info_dic.setdefault('hobbies',[1,2,3,4,5])
# print(info_dic)

# info_dic={'name':'haiyan','age':18,'sex':'male'}

# {'name':'egon','age':18,'sex':'male','hobbies':['study']}
# info_dic.setdefault('hobbies',[]).append('study')

# {'name':'egon','age':18,'sex':'male','hobbies':['study','read']}
# info_dic.setdefault('hobbies',[]).append('read')

# {'name':'egon','age':18,'sex':'male','hobbies':['study','read','sleep']}
# info_dic.setdefault('hobbies',[]).append('sleep')
# l=info_dic.setdefault('hobbies',[])
# print(l,id(l))
# print(id(info_dic['hobbies']))

# print(info_dic)



#了解
# d=info_dic.copy()
# print(d)
# info_dic.clear()
# print(info_dic)


# d=info_dic.fromkeys(('name','age','sex'),None)
# print(d)
# d1=dict.fromkeys(('name','age','sex'),None)
# d2=dict.fromkeys(('name','age','sex'),('egon',18,'male'))
# print(d1)
# print(d2)




# info=dict(name='haiyan',age=18,sex='male')
# print(info)

#
# info=dict([('name','haiyan'),('age',18)])
# print(info)