老师，运行出现这个错误，该怎么解决呢

#coding=utf-8
import pygame,time,random
SCREEN_WIDTH=600
SCREEN_HEIGHT=500
BG_COLOR=pygame.Color(0,0,0)
TEXT_COLOR=pygame.Color(255,0,0)
class MainGame():
    window = None
    my_tank = None
    enemyTankList = []
    enemyTankCount = 5
    def __init__(self):
        pass


    def startGame(self):
        pygame.display.init()
        MainGame.my_tank=Tank(300,250)
        self.creatEnemyTank()
        MainGame.window=pygame.display.set_mode((SCREEN_WIDTH,SCREEN_HEIGHT),0,32)
        pygame.display.set_caption("坦克大战")
        while True:
            time.sleep(0.02)
            MainGame.window.fill(BG_COLOR)
            self.getEvent()
            MainGame.window.blit(self.getTextSurface("敌方坦克剩余数量%d"%6),(10,10))
            MainGame.my_tank.displayTank()
            self.blitEnemyTank()
            if not MainGame.my_tank.stop:
                MainGame.my_tank.move()
            pygame.display.update()

    def creatEnemyTank(self):
        top=100
        for i in range(MainGame.enemyTankCount):
            left=random.randint(0,600)
            speed=random.randint(1,4)
            enemy=EnemyTank(left,top,speed)
            MainGame.enemyTankList.append(enemy)
    def blitEnemyTank(self):
        for enemyTank in MainGame.enemyTankList:
            enemyTank.displayTank()



    def getEvent(self):
        eventlist=pygame.event.get()
        for event in eventlist:
            if event.type==pygame.QUIT:
                self.endGame()
            if event.type==pygame.KEYDOWN:
                if event.key==pygame.K_LEFT:
                    MainGame.my_tank.direction="L"
                    MainGame.my_tank.stop=False
                    #print("按下左键，坦克向左移动")
                elif event.key==pygame.K_RIGHT:
                    MainGame.my_tank.direction = "R"
                    MainGame.my_tank.stop = False
                    #print("按下右键，坦克向右移动")
                elif event.key==pygame.K_UP:
                    MainGame.my_tank.direction = "U"
                    MainGame.my_tank.stop = False
                    #print("按下上键，坦克向上移动")
                elif event.key==pygame.K_DOWN:
                    MainGame.my_tank.direction = "D"
                    MainGame.my_tank.stop = False
                    #print("按下下键，坦克向下移动")
                elif event.key == pygame.K_SPACE:
                    pass
                    #print("发射子弹")
            if event.type == pygame.KEYUP:
                if event.key==pygame.K_DOWN or event.key==pygame.K_UP or event.key==pygame.K_RIGHT or event.key==pygame.K_RIGHT:
                    MainGame.my_tank.stop=True


    def endGame(self):
        print("谢谢使用，欢迎再次使用")
        exit()

    def getTextSurface(self,text):
        pygame.font.init()
        font=pygame.font.SysFont("kaiti",18)
        textSurface=font.render(text,True,TEXT_COLOR)
        return textSurface

class Tank():
    def __init__(self,left,top):
        self.images={
            "U":pygame.image.load("img/p1tankU.gif"),
            "D": pygame.image.load("img/p1tankD.gif"),
            "L": pygame.image.load("img/p1tankL.gif"),
            "R": pygame.image.load("img/p1tankR.gif")}
        self.direction="U"
        self.image=self.images[self.direction]
        self.rect=self.image.get_rect()
        self.rect.left=left
        self.rect.top=top
        self.speed=5
        self.flag=True



    def randDirection(self):
        num=random.randint(1,4)
        if num==1:
            return "U"
        elif num==2:
            return "D"
        elif num==3:
            return "L"
        elif num==4:
            return "R"
    def move(self):
        if   self.direction=="L":
            if self.rect.left>0:
                self.rect.left-=self.speed
        elif self.direction=="R":
            if self.rect.left+self.rect.height <SCREEN_WIDTH:
                self.rect.left+=self.speed
        elif self.direction == "U":
            if self.rect.top > 0:
                self.rect.top -= self.speed
        elif self.direction == "D":
            if self.rect.top + self.rect.height < SCREEN_HEIGHT:
                self.rect.top += self.speed
    def displayTank(self):
        self.image = self.images[self.direction]
        MainGame.window.blit(self.image,self.rect)
class EnemyTank(Tank):
    def __init__(self,left,top,speed):
        self.images={
            'U':pygame.image.load('img/enemy1U.gif'),
            'D':pygame.image.load('img/enemy1D.gif'),
            'L':pygame.image.load('img/enemy1L.gif'),
            'R':pygame.image.load('img/enemy1R.gif')
        }

        self.direction=self.randDirection()
        self.image=self.images[self.direction]
        self.rect=self.image.get_rect()
        self.rect.left=left
        self.rect.top=top
        self.speed=speed
        self.flag=True

if __name__=="__main__":
    MainGame().startGame()

老师你好，我想问一下我这里在进行迁移命令的时候为什么切换不到指定目录呢？麻烦老师给点提示

老师讲的a=3，id(3)  1531372336

我在我电脑上输入a=3 id(3)出来的一串数字跟老师的不同

这个怎么讲呢？？不太懂。

我照着敲的，访问时候弹出这个

package com.security.handle;

import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.web.access.AccessDeniedHandler;
import org.springframework.stereotype.Component;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * @author  liufupeng
 * @date  2021/5/11
 */
@Component
public class MyAccessDeniedHandler implements AccessDeniedHandler {

    @Override
    public void handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, AccessDeniedException e) throws IOException, ServletException {

        httpServletResponse.setStatus(HttpServletResponse.SC_FORBIDDEN);
        httpServletResponse.setContentType("application/json:charset=utf-8");
        PrintWriter writer = httpServletResponse.getWriter();
        writer.println("{\"code\":\"403\",\"msg\":\"无权限\"}");
        writer.flush();
        writer.close();
    }


}

package com.security.config;

import com.security.handle.MyAccessDeniedHandler;
import com.security.handle.MyAuthenticationFailHandler;
import com.security.handle.MyAuthenticationSuccessHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;

/**
 * @author liufupeng
 * @date 2021/5/8
 */
@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private MyAccessDeniedHandler myAccessDeniedHandler;

    @Override
    protected void configure(HttpSecurity http) throws Exception {

        // 表单认证
        http.formLogin()
                .loginProcessingUrl("/login") // 当发现/login时认为是登陆，需要执行UserDetailsServiceImpl
//                .successForwardUrl("/toMain") // 登陆成功 此处为post请求
//                .failureForwardUrl("/fail")
                .usernameParameter("username") //自定义username字段
                .passwordParameter("password")
                .successHandler(new MyAuthenticationSuccessHandler("/toMain"))
                .failureHandler(new MyAuthenticationFailHandler("/fail.html"))
                .loginPage("/login.html");

        //  url 拦截
        http.authorizeRequests()
                .antMatchers("/login.html", "/fail.html").permitAll() // 登陆不需要被认证
//                .antMatchers("/main1.html").hasAuthority("admin")
                .antMatchers("/main1.html").hasIpAddress("127.0.0.1")
                .anyRequest().authenticated();

        http.csrf().disable();

        http.exceptionHandling()
                .accessDeniedHandler(myAccessDeniedHandler);
    }

    @Bean
    public PasswordEncoder getPe() {
        return new BCryptPasswordEncoder();
    }
}

相反，StringBuilder 和 StringBuffer 类是对原字符串本身操作的，可以对字符串进行修改而不产生副本拷贝或者产生少量的副本。因此可以在循环中使用。

老师，这里产生的少量副本是指什么？是指调用toString方法的时候吗？

老师，请问一下为什么这个方法可以在类外面呢？

老师这一步是 干嘛的呢。

作用做什么的呢、

获取连接  是获取什么的链接

老师你好，34行的wait（）语句他可以自己单独调用的吗，还是跟23行里面的sleep(6)有关联的，程序开始运行的时候调用了ti,t2线程打印 车开走了和等车 这2句话，一起等待了6秒之后才变为True，有点没搞懂

from threading import Thread
from threading import Event
from time import sleep
'''
1.Event()可以创建一个事件管理标志，该标志(event)默认为False。
2.event.wait(timeout=None)：调用该方法的线程会被阻塞，如果设置了,
  timeout 参数，超时后，线程会停止阻塞继续执行；
'''
def car():
    #global count
    num=0
    while True:
        if even.is_set(): #判断event的标值是否为True
            print('车已经到站，可以上车')
            sleep(1)
            #count=count+1
            num=num+1
            if num % 5  == 0:
                even.clear() #将event设置为False

        else:
            print('车开走了...')
            sleep(6)
            #count=1
            even.set()  #将event设置为True

def person():
    while True:
        if even.is_set():
            print('上车')
            sleep(1)
        else:
            print('等车')
            even.wait()
            #sleep(1)

if __name__=='__main__':
    even=Event()
    #count=1
    t1=Thread(target=car)
    t2=Thread(target=person)
    t1.start()
    t2.start()

老师请问有没有spark安转的视频或者教程啊

老师，这里为什么不算违反python的方法不能重名的原则呢

#测试grid布局管理器
from tkinter import *

class Application(Frame):

    def __init__(self,master=None):  #master默认是None，实例化时传入参数root替换None
        super().__init__(master)
        self.master=master
        self.pack()
        self.createWidget()

    def createWidget(self):   #定义框内容以及属性

        self.l0=Label(self,text="用户名")
        #grid(row=0,column=0)--在0行0列放置
        self.l0.grid(row=0,column=0)

        #self.v=StringVar()
        #self.e0 = Entry(self, textvariable=self.v)
        #self.e0.grid(row=0, column=1)
        Entry(self).grid(row=0, column=1)

        self.l1 = Label(self, text="密码").grid(row=1, column=0)

        #self.v1 = StringVar()
        #self.e1 = Entry(self, textvariable=self.v1,show='*')
        #self.e1.grid(row=1, column=1)
        Entry(self,show='*').grid(row=1, column=1)

        self.l2 = Label(self, text="用户名为手机号").grid(row=0, column=2)

        Button(self,text="登录").grid(row=2, column=1,sticky=EW)  #EW，沿东西方向都有
        Button(self, text="取消").grid(row=2, column=2, sticky=E)


if __name__=="__main__":
    root=Tk()                        #创建框大小、位置以及标题
    app=Application(master=root)
    root.title("grid")
    root.geometry("400x120+450+200")
    root.mainloop()

老师请问以下红框和绿框实现的功能是一样的，这个两个写法有什么区别呢？那是说明不需要设置变量StringVar()也可以吗？还是说在特定情况下才可以？

老师，工作中那个阶段会使用到IDEA的调试功能？

老师你好，你能帮我看看以下程序为什么会出现这种错误吗？

<label for="username">
    <span>用户名：</span><input type="text"  id="username"  class="username"/>
</label><br/>
    <label for="password">
    <span>密码：</span><input type="text"  id="password"  class="password"/>
</label><br/>
    <button>登陆</button>

 <script>
        var usernameInput = document.querySelector('.username');
        var passwordInput = document.querySelector('.password');
        var btn = document.querySelector('button');

        btn.onclick = function() {
            //兼容性问题，考虑兼容IE使用 ActiveXObject()  非IE使用XMLHttpRequest()
            //        xhr = window.XMLHttpRequest?new XMLHttpRequest():new ActiveXObject("");
            var xhr = new XMLHttpRequest();
            xhr.onreadystatechange = function() {
                if (xhr.readyState == 4) {
                    if (xhr.status == 200) {
                        console.log(JSON.parse(xhr.responseText));
                    }
                }
            };

            xhr.open('post', '03post请求.php', true);

            //构建post表单数据，使用FormData类构建数据
            var datas = new FormData();
            datas.append('uname', usernameInput.value);
            datas.append('upass', passwordInput.value);
            xhr.send(datas);
        }
    </script>

<?php
     $success = array('msg'=>"ok","info"=>$POST);
    echo json_encode($success);
?>

from multiprocessing import Process
from time import sleep

class Myprocess(Process):
    def __init__(self,name):#这个name就是类里面的参数
        Process.__init__(self)
        self.name=name
    def run(self):#这个self就不需要再写个namae了 因为上面有了
        print(f"Process:{self.name}start")
        
p1=Myprocess('pcl')

p1.start()

    老师 请问报错里 为什么会出现几百行的错误 我的代码都没有那么多行

C:\Users\pcl\venv\Scripts\python.exe "C:/Users/pcl/.1aPython all exercise/线程与进程/进程实现/进程类包装.py"

Traceback (most recent call last):

  File "<string>", line 1, in <module>

  File "C:\Users\pcl\lib\multiprocessing\spawn.py", line 116, in spawn_main

    exitcode = _main(fd, parent_sentinel)

  File "C:\Users\pcl\lib\multiprocessing\spawn.py", line 125, in _main

    prepare(preparation_data)

  File "C:\Users\pcl\lib\multiprocessing\spawn.py", line 236, in prepare

    _fixup_main_from_path(data['init_main_from_path'])

  File "C:\Users\pcl\lib\multiprocessing\spawn.py", line 287, in _fixup_main_from_path

    main_content = runpy.run_path(main_path,

  File "C:\Users\pcl\lib\runpy.py", line 268, in run_path

    return _run_module_code(code, init_globals, run_name,

  File "C:\Users\pcl\lib\runpy.py", line 97, in _run_module_code

    _run_code(code, mod_globals, init_globals,

  File "C:\Users\pcl\lib\runpy.py", line 87, in _run_code

    exec(code, run_globals)

  File "C:\Users\pcl\.1aPython all exercise\线程与进程\进程实现\进程类包装.py", line 13, in <module>

    p1.start()

  File "C:\Users\pcl\lib\multiprocessing\process.py", line 121, in start

    self._popen = self._Popen(self)

  File "C:\Users\pcl\lib\multiprocessing\context.py", line 224, in _Popen

    return _default_context.get_context().Process._Popen(process_obj)

  File "C:\Users\pcl\lib\multiprocessing\context.py", line 327, in _Popen

    return Popen(process_obj)

  File "C:\Users\pcl\lib\multiprocessing\popen_spawn_win32.py", line 45, in __init__

    prep_data = spawn.get_preparation_data(process_obj._name)

  File "C:\Users\pcl\lib\multiprocessing\spawn.py", line 154, in get_preparation_data

    _check_not_importing_main()

  File "C:\Users\pcl\lib\multiprocessing\spawn.py", line 134, in _check_not_importing_main

    raise RuntimeError('''

RuntimeError: 

        An attempt has been made to start a new process before the

        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your

        child processes and you have forgotten to use the proper idiom

        in the main module:

            if __name__ == '__main__':

                freeze_support()

                ...

        The "freeze_support()" line can be omitted if the program

        is not going to be frozen to produce an executable.

Process finished with exit code 0

老师能帮我看看这个错在哪里嘛？是哪里配置错了嘛