Python day 05

day05 数据类型

今日内容

• 字典

补充

• .extend()

  users = [1,2,3,4]
  people = [5,6,7,8]
  users.extend(people)
  people.extend(users)

• pop和del的区别

  li = ["alex", "WuSir", "ritian", "barry", "wenzhou"]
  del li[2] # 仅仅是删除
  
  deleted = li.pop(2) # 在列表中删除，并将删除的此数据赋值给deleted
  print(li)
  print(deleted)
  

内容详细

1. 字典

帮助用户去表示一个事物的信息（事物是有多个属性）。

info = {"name":'刘伟达','age':18,'gender':'男','hobby':'同桌'} # 键值

# 请输出：我今天点%s,他的年龄是%s,性别是%s，他喜欢他的%s;

基本格式

data = {键:值,键:值,键:值,键:值,键:值,键:值,}

# 练习题
userinfo = {'usenrame':'glacier','password':"oldboy"}

user = input('请输入用户：')
pwd = input('请输入密码：')

if userinfo['username'] == user and userinfo['password'] == pwd:
    print('登陆成功')
else:
    print('用户名或密码错误')

1. 独有功能

   info = {"name":'glacier','age':18,'gender':'男','hobby':'python'}

   • keys，获取字典中所有的键。 ['name','age','gender','hobby']

     # for item in info.keys():
     #     print(item)

   • values，获取字典中所有的值。 ['glacier','18','男','python']

     # for item in info.values():
     #     print(item)

   • items，获取字典中的所有键值对。

     # for v1,v2 in info.items():
     #     print(v1,v2)

2. 公共功能

   • len

     info = {"name":'glacier','age':18,'gender':'男','hobby':'python'}
     print(len(info))

   • 索引

     info = {"name":'glacier','age':18,'gender':'男','hobby':'python'}
     info['name']
     info['age']

   • 切片【无】

   • 步长【无】

   • for

     info = {"name":'glacier','age':18,'gender':'男','hobby':'python'}
     
     for item in info.keys():
         print(item)
     
     for item in info.values():
         print(item)
     
     for k,v in info.items():
         print(k,v)

   • 修改（存在就修改/不存在就增加）

     # 改值
     info = {"name":'glacier','age':18,'gender':'男','hobby':'python'}
     info['age'] = 19
     print(info)
     
     # 改键
     # 删除后再增加
     del info['hobby']
     info['xxxxx'] = 'x1'

   • 删除

     info = {"name":'glacier','age':18,'gender':'男','hobby':'python'}
     
     del info['name']
     print(info)
     

重点

• int
• bool
• str
• list
• tuple
• dict