字典

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)