Python编程及项目开发 第4章-项目开发

4.7项目开发1.系统功能l增加学生信息：输入学生的基本信息并保存。l查询学生信息：根据学号或姓名查询学生信息。l删除学生信息：根据学号删除学生信息。l修改学生信息：根据学号修改学生信息。l显示所有学生信息：显示系统中所有学生的信息。l退出系统：退出程序。2.系统设计系统类的设计如图4-4所示。3.系统实现1importos2importre3classStudent:#定义类4stuID=""#类属性5name=""6sex="M"7classID="NULL"89#定义每一个属性的get方法和set方法用于获得/设置属性10defsetStuID(self,stuID):11self.stuID=stuID12defsetName(self,name):13=name14defsetSex(self,sex):15self.sex=sex16defsetClassID(self,classID):17self.classID=classID18defgetStuId(self):19returnself.stuID20defgetName(self):21return22defgetSex(self):23returnself.sex24defgetClassID(self):25returnself.classID2627classStudentManagementSystem:28def__init__(self,file_path="students.db"):29self.file_path=file_path30self.students=self.load_students()3132defload_students(self):33students=[]34ifos.path.exists(self.file_path):35withopen(self.file_path,"r")asfile:36forlineinfile:37stu_id,name,sex,class_id=line.strip().split("\t")38students.append(Student(stu_id,name,sex,class_id))39returnstudents4041defsave_students(self):42withopen(self.file_path,"w")asfile:43forstudentinself.students:44filefile.write(f"{student.stu_id}\t{}\t{student.sex}\t{student.class_id}\n")4546defadd_student(self):47stu_id=input("EnterstudentID(001-999):")48ifnotre.match("^[0-9]{3}$",stu_id)orstu_id=="000"orany(s.stu_id==stu_idforsinself.students):49print("InvalidIDorIDalreadyexists.")50return51name=input("Enterstudentname(1-5characters):")52ifnotre.match("^[a-zA-Z]{1,5}$",name):53print("Invalidname.")54return55sex=input("Entersex(M/F):").upper()56ifsexnotin["M","F"]:57print("Invalidsex.")58return59class_id=input("EnterclassID(01-99):")60ifnotre.match("^[0-9]{2}$",class_id)orclass_id=="00":61print("InvalidclassID.")62return63self.students.append(Student(stu_id,name,sex,class_id))64self.save_students()65print("Studentaddedsuccessfully.")6667defquery_student(self):68query_by=input("Queryby(ID/Name):").lower()69ifquery_by=="id":70stu_id=input("EnterstudentID:")71student=next((sforsinself.studentsifs.stu_id==stu_id),None)72elifquery_by=="name":73name=input("Enterstudentname:")74student=next((sforsinself.studentsif.lower()==name.lower()),None)75else:76print("Invalidqueryoption.")77return78ifstudent:79print(student)80else:81print("Studentnotfound.")83defdelete_student(self):84stu_id=input("EnterstudentIDtodelete:")85student=next((sforsinself.studentsifs.stu_id==stu_id),None)86ifstudent:8787self.students.remove(student)88self.save_students()89print("Studentdeletedsuccessfully.")90else:91print("Studentnotfound.")9293defmodify_student(self):94stu_id=input("EnterstudentIDtomodify:")95student=next((sforsinself.studentsifs.stu_id==stu_id),None)96ifstudent:97=input("Enternewname:")98student.sex=input("Enternewsex(M/F):").upper()99student.class_id=input("EnternewclassID:")100self.save_students()101print("Studentmodifiedsuccessfully.")102else:103print("Studentnotfound.")105defdisplay_all_students(self):106ifself.students:107forstudentinself.students:108print(student)109else:110print("Nostudentsfound.")112defrun(self):113whileTrue:114print("\nStudentManagementSystem")115print("1.AddStudent")116print("2.QueryStudent")117print("3.DeleteStudent")118print("4.ModifyStudent")119print("5.DisplayAllStudents")120print("0.Exit")121choice=input("Enteryourchoice:")122ifchoice=="1":123self.add_student()124elifchoice=="2":125self.query_student()126elifchoice=="3":127self.delete_student()128elifchoice=="4":129self.modify_student()130elifchoice=="5":131self.display_all_students()132132elifchoice=="0":133print("Exitingthesystem.")134break135else:136print("Invalidchoice.Pleasetryagain.")程序运行结果为：1.增加学生信息2.查询学生信息3.删除学生信息0.退出请选择：说明：(1)该程序使用文件保存学生信息，关于文件的操作请参阅相关章节。(2)实现该系统的方法有多种，用户可以修改并完善该系统。1.项目需求l支持变压器/断路器/隔离开关等设备信息管理（添加、删除、查询）。设备属性包括：名称、ID、型号、安装位置、运行日期。l设备状态实时监控（正常/警告/故障）。l维护管理：维护记录管理（时间、人员、维护内容维护周期提醒；故障记录及处理跟踪。l用户权限：分级权限管理（管理员/操作员操作日志记录；统计报表；设备状态统计；维护记录查询；故障率分析。2.项目设计系统类的设计如图4-5所示。3.项目实现11classDevice:2"""设备基类""" 3definit(self,id,name,location):4self.id=id5=name6self.location=location7self.status="normal"#normal/warning/fault8self.install_date=datetime.now()910defcheck_status(self):11"""检查设备状态"""12pass14classTransformer(Device):15"""变压器类"""16definit(self,id,name,location,capacity):17super().init(id,name,location)18self.capacity=capacity#容量(kVA)19self.temperature=45.02021defcheck_status(self):22ifself.temperature>85:23self.status="fault"24elifself.temperature>65:25self.status="warning"26else:27self.status="normal"2829classCircuitBreaker(Device):30"""断路器类"""31definit(self,id,name,location,rated_current):32super().init(id,name,location)33self.rated_current=rated_current#额定电流34self.current_load=0.03536defcheck_status(self):37ifself.current_load>self.rated_current*1.2:38self.status="fault"39elifself.current_load>self.rated_current:40self.status="warning"41else:42self.status="normal"4344classMaintenanceRecord:45"""维护记录类"""46definit(self,device_id,maintainer,content):47self.time=datetime.now()48self.device_id=device_id4949self.maintainer=maintainer50self.content=content5152classDeviceManager:53"""设备管理类"""54definit(self):55self.devices={}#ID到设备的映射56self.maintenance_records=[]5758defadd_device(self,device):59ifdevice.idinself.devices:60raiseValueError("设备ID已存在")61self.devices[device.id]=device6263deffind_device(self,device_id):64returnself.devices.get(device_id)6566defrecord_maintenance(self,device_id,maintainer,content):67record=MaintenanceRecord(device_id,maintainer,content)68self.maintenance_records.append(record)6970defget_device_status(self,device_id):71device=self.find_device(device_id)72ifdevice:73device.check_status()74returndevice.status75returnNone7677classUser:78"""用户基类"""79definit(self,username,role):80self.username=username81self.role=role#admin/operator83defcan_manage_devices(self):84returnself.role=="admin"86classStationSystem:87"""变电站管理系统"""88definit(self):89self.device_manager=DeviceManager()90self.users={}91self.current_user=None9293deflogin(self,username,password):94#简化登录验证95user=self.users.get(username)96ifuseranduser.password==password:97self.current_user=user98