列表 | 元组 | 字典 |
---|---|---|
[] | () | {} |
list | tuple | dict |
ele | ele | key:value |
定义
dict1 = {}#空字典
dict2 = dict()
dict3 ={'ID':03957348953894','name':'lucky','age':18}
dict4 =dict([('name','lucky'),('age',18)])
print(dict4)
格式:dict6[key] = value
特点:按照上面的格式,如果在字典中存在同名的key,则发生值的覆盖,如果没有同名的key,则实现的_添加功能_
dict6['brand'] = 'huawei'
print(dict6)#{'brand':'huawei'}
dict6['brand'] = 'mi'
print(dict6)
dict6['type'] = 'p30pro'
dict6['price'] = 9000
dict6['color'] = 黑色
案例
用户注册功能:username、password、email、phone
print('---------欢迎来到注册界面----------')
database = []
while True:
username = input('请输入用户名:')
password = input('请输入密码:')
repassword = input('确认密码:')
email = input('请输入邮箱:')
phone = input('输入手机号:')
#定义一个字典
user = {}
#将信息存到字典中
user['username'] = username
if password == repassword:
user['password'] = password
else:
print('两次密码不一致,重新输入……')
continue
user['phone'] = phone
#保存到数据库
database.append(user)
answer = input('是否继续注册?(y/n)')
if answer != 'y':
break
print(database)
修改:
list1[index] = new_value
dict1[key] = new _value
查询元素:
list1[index] —>element
dict1[key] —> value
案例
list1 = [3,5,7,8]
print(list1[2])
dict1 = {'1':'张三','2':'李四','3':'王五'}
print(dict1['2'])
dict2 = {'张三':100,'李四':99,'王五':98,'老刘':97}
print(dict2['王五'])
#考试分数大于99分的人,尝试对字典进行遍历
for key,value in dict2:
print(key,value)#遍历的结果是:就字典的key。
字典里的函数:
#接着上面的
print(dict2.items())
for i in dict2.items():
print(i)
#考试成绩大于98分的人:
for key,value in dict2.items():
if value>98:
print(key)
运行结果:
7
李四
98
dict_items([(‘张三’, 100), (‘李四’, 99), (‘王五’, 98), (‘老刘’, 97)])
(‘张三’, 100)
(‘李四’, 99)
(‘王五’, 98)
(‘老刘’, 97)
张三
李四
print(dict2.get('赵飞',99)
del dict[key]
dict.pop(key,[default])
dict.popitem()
dict.clear()
list1 = [3,6,32,6]
del list1[1]
print(list1)
dict2 = {'张三':100,'李四':99,'王五':98,'老刘':97}
del dict1['王五']
print(dict1)
#del dict1['wogiao']
#字典的内置函数
#dict1.remove('李四'),,,,,,,,pop(key,[default])根据key删除字典中的键值对,删除成功,返回value
dict1.pop('李四')
print(result)
result = dict.pop('老铁','80')
print(result)
print(dict1)
其他内置函数
update() [ ] + [ ]合并操作
fromkeys ( seq )
#dict1 = dict1 + dict2 报错!
dict1 = {0:'tom',1:'jack',2:'lucy'}
dict2 = {0:'lily','4':'ruby'}
result = dict1.update(dict2)
print(result)
print(dict1)
list1 = ['aa','bb','cc']
new_dict = dict.fromkeys(list1,10)
print(new_dict)
运行结果:
None
{0: ‘lily’, 1: ‘jack’, 2: ‘lucy’, ‘4’: ‘ruby’}
{‘aa’: 10, ‘bb’: 10, ‘cc’: 10}
本文地址:https://blog.csdn.net/a_pogrammer/article/details/107443277
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Day03_数据类型介绍&Python运算符&IF分支
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