字典

最新推荐文章于 2025-08-12 09:03:23 发布

转载最新推荐文章于 2025-08-12 09:03:23 发布 · 71 阅读

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/ugfly/p/7214007.html

本文详细介绍了Python中字典的基本操作方法，包括如何存取、更新、删除字典中的元素，以及如何遍历字典等内容。此外，还提供了实用的例子帮助理解各种字典操作的应用场景。

# info=['ff','male',18,180,75]
#
#
# info_dic={'name':'ff','age':18,'sex':'male'}
存/取  删除   键s值s 键值对      查

# 常用操作：
#
# 　　　　存/取
# info_dic={'name':'ff','age':18,'sex':'male'}
# print(info_dic['name11111111'])
# print(info_dic.get('name',None )) 

#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('name',None))# 默认取最后一个值
# print(info_dic)

# print(info_dic.popitem( ))    #默认取最后一个key:value键值对
# print(info_dic)

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

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

# del info_dic['name']


#
# 　　　　键s，值s，键值对
info_dic={'name':'ff','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', 'ff')
#     print(k,v)



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

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



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

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

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

# {'name':'ff','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'),('ff',18,'male'))
# print(d1)
# print(d2)




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

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