1. 为什么这里Drawing类里的account能调用Account里的name

2. expenseTotal不需要在def__init__()括号里定义吗

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    (,){
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        {
            .();
            .(,,);
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            .();
            .();
            ..();
        } () {
            .();
        }{
            (){
                {
                    .();
                } () {
                    .();
                }
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        (){
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    ([] ) {
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}

报错，

"C:\Program Files\Java\jdk1.8.0_201\bin\java.exe" "-javaagent:D:\program files\JetBrains\IntelliJ IDEA 2019.1\lib\idea_rt.jar=49766:D:\program files\JetBrains\IntelliJ IDEA 2019.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_201\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_201\jre\lib\rt.jar;D:\workspace\jdbcDemo\out\production\jdbcDemo;D:\workspace\jdbcDemo\lib\mysql-connector-java-5.1.47.jar" com.bjsxt.JdbcTest

Sat Nov 02 21:15:19 CST 2019 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:965)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3978)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3914)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:871)

at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1714)

at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1224)

at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2199)

at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2230)

at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2025)

at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:778)

at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:423)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)

at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)

at java.sql.DriverManager.getConnection(DriverManager.java:664)

at java.sql.DriverManager.getConnection(DriverManager.java:247)

at com.bjsxt.JdbcTest.insertDepartments(JdbcTest.java:17)

at com.bjsxt.JdbcTest.main(JdbcTest.java:44)

Process finished with exit code 0

老师怎么解决？？？

index_url ='https://www.kuaidaili.com/usercenter/overview'
index_req = Request(index_url,headers =headers)
index_resp = opener.open(index_req)
print(index_resp.read().decode())

请问这里是什么意思，在登录账号后，还发送请求是为啥

老师我把找到问题在哪了///        给老师添麻烦了

headers={"UserAgent":UserAgent().random}里的UserAgent写错了，应该这么写User-Agent。

String s = new String("北京尚学堂");

老师，这个代码里是有两个对象么？一个是new,一个是传入的？

请问一下这个错误是什么意思啊，调试了半天没有用

minlenth属性是谷歌，火狐，ie都取消了它的作用？这三个浏览器中并没有提示长度不够

class Employee:
    def __init__(self, name, age, salary):
        self.name = name
        self.age = age
        self.salary = salary

    @property
    def salary(self):
        print('薪资是:', self.salary)
        return self.salary

    @salary.setter
    def salary(self, salary):
        if 0 < salary <= 1000000:
            self.salary = salary
        else:
            print('请重新输入')

@property装饰器里的salary要是私有的吗，self.__salary就运行就出错

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body{
            background-color: red;
        }
        @media screen and (max-width=768px) {
            body{
                background-color: red;
            }

           
        }
        @media screen and (mix-width=768px) and (max-width=992px){
            body{
                background-color: green;
            }
        }
        @media screen and (max-width=992px){
            body{
                background-color: indianred;
            }
        }
    </style>
</head>

<body>
   
</body>

</html>

老师，为什么我按照视频中老师的代码写了，改变屏幕宽度背景颜色不会改变呢？

<view class="content">
    <button wx:if="{{isshow}}" open-type="getUserInfo" bindgetuserinfo='getuserinfo'>点击授权</button>
    <view class="userinfo" wx:else>
        <view class="img"><image src="{{avatarUrl}}"></image></view>
        <view class="nickname">{{nickName}}</view>
    </view>
</view>

data: {
        isshow:true,
        nickName:'',
        avatarUrl:''
    },
    //1、点击授权信息
    getuserinfo:function(e){
        console.log(e);
        this.setData({
            isshow:false,
            nickName:e.detail.userInfo.nickName,
            avatarUrl:e.detail.userInfo.avatarUrl,
        })
    },

老师你好，我遇到个问题，就是这边授权获取头像的时候没办法获取，点击 按钮 之后不会有弹窗出来让我去授权登录，不知道是哪边出了问题

y^=θ^TXi=hθXi=(WXi)=θXi

不是应该是XiW=Xiθ吗

老师，询问一个关于修改文件、文件夹所属者和所属组的问题：

如视频中所示，将文件test的所属者改为bz时，其所属组依旧是root，不是很理解所属者和所属组这层关系。

我自己的理解是，所属者改为bz了，那么bz应该是属于这个文件所属组的吧，但是所属者bz和所属组root又没有关系

这节课声音不是很清晰。。。。。。。。。。。。。。

为什么我激活虚拟环境后，没出现（env_name）的前缀呢？是没激活成功吗