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)