有效沟通问答-【官方】百战程序员_IT在线教育培训机构

# coding=utf-8
import sys


class AA:
    def __init__(self):
        print("构造函数！！！")

    def __del__(self):
        print("对象被系统回收之前被调用的方法！！！")


def func(aaa):
    print("引用两次！！！")


a = AA()
print(f"被调用的次数：{sys.getrefcount(a)}")
func(a)
print(f"被调用的次数：{sys.getrefcount(a)}")

老师为什么结果还是2呢

Python 全系列/第四阶段：函数式编程和核心特性/内存管理（旧） 12047楼

总是感觉很奇怪不用定位白色导航那里总是把我的li 标签挤得页面很乱是哪里出问题了吗

WEB前端全系列/第一阶段：HTML5+CSS3模块/商城官网项目 12048楼

/* 黑色导航开始 */
.black-nav{
 width: 100%;
 height: 40px;
 background-color: #333;  
 line-height: 40px;
 
}
.wrap{
    width: 1226px;
    margin: 0 auto;
    /* position: relative; */
}
.left-nav{
    float: left;
}
.right-nav{
    float: right;
}
.black-nav li{
    float: left;
    position: relative;
}
.black-nav a{
    color: #b0b0b0;
    font-size: 12px;
}
.black-nav span{
    color: #424242;
    margin: 0 3.6px;
}
.black-nav a:hover{
    color: #fff;
}
.download{
    width: 124px;
    height: 0;
    background-color: #fff;
    position:absolute;
    top: 40px;
    left: -50%;
    display: none;
    box-shadow: 0 1px 5px #333 ;
    transition: all 0.5s;
    /* margin-left: -62px; */
}
.download img{
    width: 90px;
    margin: 18px auto 0;
}
.left-nav li:hover>.download{
    height: 148px;
    display: block;
   
}
.download p{
    color: #424242;
    font-size: 14px;
    line-height: 14px;
}
.triangle{
    width: 0;
    height: 0;
    border-bottom: 8px solid #fff;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    position: absolute;
    bottom: 0px;
    right: 50%;
    margin-left: -8px;
    display: none;
}
.left-nav li:hover>.triangle{
    display: block;
}
.cart{
    width: 120px;
    height: 40px;
    background: #424242;
    margin-left: 20px;
}
.cart span{
    color: #b0b0b0;
}
.cart:hover{
    background: #fff;
}
.cart:hover>a{
    color: #ff6700;
}
.cart i{
    font-style: normal;
    padding-left: 5px;
    position: relative;
}
.cart-1{
    width: 320px;
    height: 0px;
    position: absolute;
    top: 40px;
    right: 0;
    box-shadow: 0 1px 5px rgba(0,0,0,0.2);
    transition: all 0.5s;
    line-height: 100px;
}
.cart:hover>.cart-1{
    height: 100px;
}

/* 黑色导航结束 */

/* 白色导航开始 */
.withe-nav{
    width: 100%;
    height: 100px;
    background: #fff;
    position: relative;
    clear: both;
    line-height: 100px;
}
.logo{
    float: left;
}
.white-left-nav{
    width: 850px;
    float: left;
}
.white-right-nav{
    width: 296px;
    float: right;
}
.logo{
    width: 56px;
    height: 56px;
    margin-top: 22.5px;
}
.logo img{
    width: 56px;
    height: 56px;
    left: 0;
}
.white-left-nav li{
    padding: 5px 0 0 30px;
    float: left;
    box-sizing: border-box;
}
.white-left-nav li a{
    color: #333;
    font-size: 16px;
}
.white-left-nav>ul>li>a:hover{
    color: #ff6700;
}
.white-left-nav ul{
    margin-left: 113px;
}
.white-right-nav input{
    width: 244px;
    height: 50px;
    line-height: 50px;
    padding: 0 10px;
    font-size: 14px;
    box-sizing: border-box;
    border: 1px solid #e0e0e0;
    margin-top: 25px;
}
.white-right-nav button{
    width: 52px;
    height: 50px;
    font-size: 24px;
    line-height: 50px;
    background-color: #fff;
    color: #616161;
    box-sizing: border-box;
    border: 1px solid #e0e0e0;
    border-left: 0;
    margin-top: 25px;
    float: right;
}
.white-right-nav button:hover{
    background-color: #ff6700;
    color: #fff;
}
.item{
    width: 100%;
    height: 229px;
    position: absolute;
    top: 100px;
    left: 0;
}



/* 白色导航结束 */

WEB前端全系列/第一阶段：HTML5+CSS3模块/商城官网项目 12049楼

<!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>小米官网</title>
    <link rel="stylesheet" href="./iconfont.css">
    <link rel="stylesheet" href="./rests.css">
    <link rel="stylesheet" href="./mi.css">
</head>
<body>
    <!-- 黑色导航开始 -->
    <div class="black-nav">
        <div class="wrap">
            <ul class="left-nav">
                <li><a href="#">小米商城</a><span>|</span></li>
                <li><a href="#">MIUI</a><span>|</span></li>
                <li><a href="#">loT</a><span>|</span></li>
                <li><a href="#">云服务</a><span>|</span></li>
                <li><a href="#">有品商城</a><span>|</span></li>
                <li><a href="#">天星科技</a><span>|</span></li>
                <li><a href="#">小爱开放平台</a><span>|</span></li>
                <li><a href="#">企业团购</a><span>|</span></li>
                <li><a href="#">资质证件</a><span>|</span></li>
                <li><a href="#">协议规则</a><span>|</span></li>
                <li>
                    <a href="#">下载APP</a>
                    <span>|</span>
                    <div class="download">
                        <img src="./image/download.png" alt="">
                        <p>小米商城App</p>
                    </div>
                    <!-- 三角形 -->
                    <div class="triangle"></div>
                </li>
                <li><a href="#">智能生活</a><span>|</span></li>
                <li><a href="#">Select</a></li>
            </ul>
            <ul class="right-nav">
                <li><a href="">登陆</a><span>|</span></li>
                <li><a href="">注册</a><span>|</span></li>
                <li><a href="">消息通知</a></li>
                <li class="cart">
                    <a href="#">
                        <i class="iconfont">&#xe70b;</i>
                        <i>购物车</i>
                    </a>
                    <div class="cart-1">还没有东西</div>
                </li>
            </ul>
        </div>
    </div>
    <!-- 黑色导航结束 -->
    <!-- 白色导航开始 -->
    <div class="withe-nav">
        <div class="wrap">
            <div class="logo">
                <img src="./image/logo-mi2.png" alt="">
            </div>
            <div class="white-left-nav">
                <ul>
                    <li>
                        <a href="#">小米手机</a>
                        <div class="item">
                            <div class="wrap">
                                <ul>
                                    <li>
                                        <a href="#">
                                           <div><img src="./image/item.webp" alt=""</div> 
                                           <p>小米pro</p>
                                           <p>5200元</p>
                                        </a>
                                    </li>
                                    <li>
                                        <a href="#">
                                           <div><img src="./image/item.webp" alt=""</div> 
                                           <p>小米pro</p>
                                           <p>5200元</p>
                                        </a>
                                    </li>
                                    <li>
                                        <a href="#">
                                           <div><img src="./image/item.webp" alt=""</div> 
                                           <p>小米pro</p>
                                           <p>5200元</p>
                                        </a>
                                    </li>
                                    <li>
                                        <a href="#">
                                           <div><img src="./image/item.webp" alt=""</div> 
                                           <p>小米pro</p>
                                           <p>5200元</p>
                                        </a>
                                    </li>
                                    <li>
                                        <a href="#">
                                           <div><img src="./image/item.webp" alt=""</div> 
                                           <p>小米pro</p>
                                           <p>5200元</p>
                                        </a>
                                    </li>
                                                                 
                                </ul>
                            </div>                          
                        </div>
                    </li>
                    <li>
                        <a href="#">红米手机</a>
                    </li>
                    <li>
                        <a href="#">电视</a>
                    </li>
                    <li>
                        <a href="#">笔记本</a>
                    </li>
                    <li>
                        <a href="#">平板</a>
                    </li>
                    <li>
                        <a href="#">家电</a>
                    </li>
                    <li>
                        <a href="#">路由器</a>
                    </li>
                    <li>
                        <a href="#">服务</a>
                    </li>
                    <li>
                        <a href="#">社区</a>
                    </li>
                </ul>
            </div>
            <div class="white-right-nav">
                <input type="text" placeholder="洗衣机">
               
                <button>^</button>
            </div>
        </div>
    </div>  
    <!-- 白色导航结束 -->
</body>
</html>

WEB前端全系列/第一阶段：HTML5+CSS3模块/商城官网项目 12050楼

pc电脑端的显示器屏幕大小也不一样啊，为啥一般不用设置百分比

Python 全系列/第七阶段：网页编程基础/CSS盒子模型 12051楼

我的前端页面是这样的：

add users(() {
            ().(() {
                username = ().()userage = ().()obj = {username:usernameuserage: userage}objJson = .(obj)

                .({
                    : : : data: objJson: (res) {
                        (res)}})})})

后端控制器：

com.kenson.controllercom.kenson.pojo.Usersorg.springframework.http.MediaTypeorg.springframework.stereotype.org.springframework.web.bind.annotation.org.springframework.web.bind.annotation.org.springframework.web.bind.annotation.javax.servlet.http.HttpServletRequestjavax.servlet.http.HttpServletResponsejava.io.IOExceptionjava.io.PrintWriter()
UsersController {

    ()
    (Users usersHttpServletRequest requestHttpServletResponse response) {
        System..println(+ users){
            PrintWriter writer = response.getWriter()writer.print()writer.flush()writer.close()} (IOException e) {
            e.printStackTrace()}
    }

    (value = produces = MediaType.+ )
    String (Users users) {
        }
}

但是测试的时候alert 无法弹出 “成功”。但是查看请求已经返回成了。

tomcat使用的 tomcat8.5.

微服务/第一阶段：SSM 框架和项目开发/（旧）SpringMVC 12052楼

怎么会有错误呢？还出现了负数

package 常用类;

//效率测试
public class ZiFuXuLie {
    public static void main(String[] args) {
        /**使用String进行字符串的拼接*/
        String s="";
        long num1=Runtime.getRuntime().freeMemory();
        long time1=System.currentTimeMillis();
        for (int i=0;i<5000;i++){
            s=s+i;
        }
        long num2=Runtime.getRuntime().freeMemory();
        long time2=System.currentTimeMillis();
        System.out.println("String占用内存："+(num1-num2));
        System.out.println("String占用时间："+(time2-time1));

        /**使用StringBuilder进行字符串的拼接*/
        StringBuilder sb=new StringBuilder("");
        long num3=Runtime.getRuntime().freeMemory();
        long time3=System.currentTimeMillis();
        for (int i=0;i<5000;i++){
            sb.append(i);
        }
        long num4=Runtime.getRuntime().freeMemory();
        long time4=System.currentTimeMillis();
        System.out.println("StringBuilder占用内存："+(num3-num4));
        System.out.println("StringBuilder占用时间："+(time4-time3));
    }
}

JAVA 全系列/第二阶段：JAVA 基础深化和提高/常用类 12053楼

这一节相关安装包链接无法打开，可以提供个新的吗

毕设项目/第一阶段：各种开发环境的使用/JDK的安装 12054楼

文档对不上课程哎，是我卡了吗

JAVA 全系列/第六阶段：项目管理与SSM框架/Mybatis 12055楼

老师为什么我用str也可以实现和format的语句有什么区别吗

Python 全系列/第一阶段：Python入门/函数和内存分析 12056楼

package com.itbaizhan;

import java.util.Arrays;

//测试二分法查找
public class TestBinarySearch {
    public static void main(String[] args) {
        int[ ] arr = { 30,20,50,10,80,9,7,12,100,40,8};//定义一个数组
        int searchWord = -20;    //所要查找的数(元素)
        Arrays.sort(arr);       //二分法查找前，一定要对数组进行排序
        System.out.println(Arrays.toString(arr));

        System.out.println(searchWord+"元素的索引： "+binarySearch(arr,searchWord));

    }
    public static int binarySearch(int[] array,int value){
        int low = 0;    //定义数组的第一个位置
        int high = array.length -1; //数组的长度减去low(low占一个位置)
        while (low <= high){        //从小到大进行排序
            int middle = (low+high)/2;  //取一个中间数mid
            if(value==array[middle]){  //如果查找值等于mid位置的值，返回mid(等于查找值的位置)的位置
                return middle;
            }
            if (value>array[middle]){
                low = middle+1;
            }
            if (value<array[middle]) {
                low = middle-1;
            }
        }
            return  -1;
    }
}

老师我这个代码写出来，当我把数改为数组里面没有的数值，run的时候却没有返回-1.我的代码和视频里面的一样

JAVA 全系列/第一阶段：JAVA 快速入门/数组和数据存储 12057楼

老师那个代码画棋盘，我有点不太理解，可以详细说一下代码的意义吗？或者有没有更简单的方法去做这个棋盘

turtle

width = num = x1 = [(-)(-+width*num)]
y1 = [(-)(--width*num)]
t = turtle.Pen()
t.speed()
i (num+):
    t.penup()
    t.goto(x1[][]x1[][]-*i)
    t.pendown()
    t.goto(x1[][]x1[][]-*i)

i (num+):
    t.penup()
    t.goto(y1[][]+*iy1[][])
    t.pendown()
    t.goto(y1[][]+*iy1[][])

t.hideturtle()   turtle.done()

Python 全系列/第一阶段：Python入门/控制语句 12058楼

我在添加了，怎么显示这样？？

JAVA 全系列/第六阶段：项目管理与SSM框架/Spring旧 12059楼

稍微修改后的代码

turtle
p = turtle.Pen()
radius = [x*x ()]
colors = []
p.width = ri (radius((radius))):
    p.penup()
    p.goto(-r)
    p.pendown()
    p.color(colors[i%(colors)])
    p.circle(r)
turtle.done

Python 全系列/第一阶段：Python入门/控制语句 12060楼

同学您好