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Python 全系列/第十五阶段:Python 爬虫开发/scrapy框架使用 3317楼
JAVA 全系列/第二阶段:JAVA 基础深化和提高/常用类 3319楼
Python 全系列/第十六阶段:数据结构与算法/算法与数据结构(旧) 3321楼

package com.rongqi;

import jdk.dynalink.beans.StaticClass;

import java.util.Stack;

public class StackTest {
    public static void main(String[] args) {
        //实例化栈容器
        Stack<String> stack = new Stack<>();
        //将元素添加到栈容器
        stack.push("a");
        stack.push("b");
        stack.push("c");

        //判断栈容器中的元素是否为空
        System.out.println(stack.empty());
        //查看栈顶元素(不会删掉栈顶元素)
        System.out.println(stack.peek());
        //返回元素在容器中的位置

        System.out.println(stack.search("c"));
        //获取栈容器的元素(删掉栈顶元素)
        String p1 = stack.pop();
        System.out.println(p1);
        String p2 = stack.pop();
        System.out.println(p2);
        String p3 = stack.pop();
        System.out.println(p3);


        StackTest stackTest = new StackTest();
        stackTest.summmry();

    }




        public void summmry(){
            String str="...{.....[......(...)..].....}...(..)..[...]...{...}...";
            //实例化stack
            Stack<String> stack1 = new Stack<>();

            boolean flag = true;
            for (int i =0;i<str.length();i++){

                char c = str. charAt(i);


                if (c=='{'){
                    stack1.push("}");
                }
                if (c=='['){
                    stack1.push("]") ;
                }
                if (c=='('){
                    stack1.push(")");
                }
                if (c==')'||c==']'||c=='}'){
                    if (stack1.empty()){
                        flag = false;
                        break;
                    }
                    String x= stack1.pop();
                    if (x.charAt(0)!=c){
                        flag = false;
                        break;
                    }
                }



            }
            if (!stack1.empty()){
                flag = false;
            }
            System.out.println(flag);
        }






}
false
c
1
c
b
a
false

为什么打印的是false啊

JAVA 全系列/第二阶段:JAVA 基础深化和提高/容器(旧) 3322楼

image.png

from tkinter import *
import webbrowser

class Application(Frame):
    def __init__(self,master=None):
        super().__init__(master)
        self.master = master
        self.pack()
        self.createWidget()

    def createWidget(self):
        self.w1=Text(root,width=40,height=12,bg="gray")
        self.w1.pack()

        self.w1.insert(1.0,"0123456789\nabcdefg")
        self.w1.insert(2.3,"锄禾日当午,汗滴禾下土\n")

        Button(self,text="重复插入文本",command=self.insertText).pack(side="left")
        Button(self,text="返回文本",command=self.returnText).pack(side="left")
        Button(self,text="添加图片",command=self.addImage).pack(side="left")
        Button(self,text="添加组件",command=self.addWidget).pack(self="left")
        Button(self,text="通过tag精准控制文本",command=self.textTag).pack(side="left")

    def insertText(self):

        self.w1.insert(INSERT,'Gaoqi')

        self.w1.insert(END,'[sxt]')
        self.w1.insert(1.8, "gaoqi")

    def returnText(self):
        print(self.w1.get(1.2,1.6))

        print("所有文本内容:\n"+self.w1.get(1.0,END))
    def addImage(self):
        self.photo = PhotoImage(file="imge01/io.jpg")
        self.w1.image_create(END,image=self.photo)

    def addWidget(self):
        b1 = Button(self.w1,text='爱上学问题')
        self.w1.window_create(INSERT,window=b1)

    def textTag(self):
        self.w1.delete(1.0,END)
        self.w1.insert(INSERT,"good good study day day up!\n北京尚学堂\n百战程序员\n百度搜一下")
        self.w1.tag_add("good",1.0,1.9)
        self.w1.tag_config("good",background="yellow",foreground="red")

        self.w1.tag_add("baidu",4.0,4.2)
        self.w1.tag_config("baidu",underline=True)
        self.w1.tag_bind("baidu","<Button-1>",self.webshow)

    def webshow(self,event):
        webbrowser.open("http://www.baidu.com")









if __name__== '__main__':
    root = Tk()
    root.geometry("400x300+200+300")
    app = Application(master=root)
    root.mainloop()

image.png

Python 全系列/第二阶段:Python 深入与提高/GUI编程(隐藏) 3326楼
JAVA 全系列/第八阶段:SpringBoot与MybatisPlus/Spring Boot(旧) 3327楼
JAVA 全系列/第二阶段:JAVA 基础深化和提高/多线程技术(旧) 3328楼

老师好:

          示例三,视频里老师测试的两种结果是一样的吧,没看出有什么区别,

第一种:

SQL> select last_name,job_id from employees where job_id like 'SA_%';
LAST_NAME                 JOB_ID
------------------------- ----------
Abel                      SA_REP
Ande                      SA_REP
Banda                     SA_REP
Bates                     SA_REP
Bernstein                 SA_REP
Bloom                     SA_REP
Cambrault                 SA_MAN
Cambrault                 SA_REP
Doran                     SA_REP
Errazuriz                 SA_MAN
Fox                       SA_REP
Grant                     SA_REP
Greene                    SA_REP
Hall                      SA_REP
Hutton                    SA_REP
Johnson                   SA_REP
King                      SA_REP
Kumar                     SA_REP
Lee                       SA_REP
Livingston                SA_REP
LAST_NAME                 JOB_ID
------------------------- ----------
Marvins                   SA_REP
McEwen                    SA_REP
Olsen                     SA_REP
Ozer                      SA_REP
Partners                  SA_MAN
Russell                   SA_MAN
Sewall                    SA_REP
Smith                     SA_REP
Smith                     SA_REP
Sully                     SA_REP
Taylor                    SA_REP
Tucker                    SA_REP
Tuvault                   SA_REP
Vishney                   SA_REP
Zlotkey                   SA_MAN
35 rows selected

第二种:

SQL> select last_name,job_id from employees where job_id like 'SA\_%' escape '\';
LAST_NAME                 JOB_ID
------------------------- ----------
Abel                      SA_REP
Ande                      SA_REP
Banda                     SA_REP
Bates                     SA_REP
Bernstein                 SA_REP
Bloom                     SA_REP
Cambrault                 SA_MAN
Cambrault                 SA_REP
Doran                     SA_REP
Errazuriz                 SA_MAN
Fox                       SA_REP
Grant                     SA_REP
Greene                    SA_REP
Hall                      SA_REP
Hutton                    SA_REP
Johnson                   SA_REP
King                      SA_REP
Kumar                     SA_REP
Lee                       SA_REP
Livingston                SA_REP
LAST_NAME                 JOB_ID
------------------------- ----------
Marvins                   SA_REP
McEwen                    SA_REP
Olsen                     SA_REP
Ozer                      SA_REP
Partners                  SA_MAN
Russell                   SA_MAN
Sewall                    SA_REP
Smith                     SA_REP
Smith                     SA_REP
Sully                     SA_REP
Taylor                    SA_REP
Tucker                    SA_REP
Tuvault                   SA_REP
Vishney                   SA_REP
Zlotkey                   SA_MAN
35 rows selected


JAVA 全系列/第三阶段:数据库编程/SQL 语言 3329楼

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