python学生信息管理系统

用python建立学生信息管理系统，实现录入，查找，删除，修改，排序，统计，显示，退出等功能

filename='student.txt'

import os
def menu():
    print("===================学生信息管理系统=====================")
    print("-----------------------功能菜单------------------------")
    print("\t\t1.录入学生信息")
    print("\t\t2.查找学生信息")
    print("\t\t3.删除学生信息")
    print("\t\t4.修改学生信息")
    print("\t\t5.排序")
    print("\t\t6.统计学生总人数")
    print("\t\t7.显示所有学生的信息")
    print("\t\t0.退出")
    print("-------------------------------------------------------")

def main():
    while True:
        menu()
        choice=int(input("请选择"))
        if choice in [0,1,2,3,4,5,6,7]:
            if choice==0:
                answer=input("您确定要退出系统么？y/n")
                if answer =="y" or answer =="Y":
                    print ("谢谢您的使用！")
                    break #"break可以退出多重循环么"
                else:
                    continue
            elif choice==1:
                insert() #录入信息
            elif choice==2:
                search()
            elif choice==3:
                delete()
            elif choice==4:
                modify()
            elif choice==5:
                sort()
            elif choice==6:
                total()
            elif choice==7:
                show()

def insert():
    student_list=[]
    while True:
        id=input("请输入ID：")
        if not id:
            break
        name=input("请输入姓名：")
        if not name:
            break
        try:
            english=int(input("请输入英语成绩:"))
            python=int(input("请输入python成绩:"))
            java= int(input("请输入java成绩:"))
        except BaseException as e:
            print("出错了",e)
            continue

        #将录入的信息保存到字典里去
        student={"id":id,"name":name,"english":english,"python":python,"java":java}
        #将学生信息添加到列表中
        student_list.append(student)
        answer=input("是否继续添加？y/n\n")
        if answer == "y" or answer == "Y":
            continue
        else:
            break

    #调用save()函数
    save(student_list)
    print('学生信息录入完毕！')

def save(lst):
    try:
        stu_txt=open(filename,'a',encoding='utf-8')
    except:
        stu_txt=open(filename,'w',encoding='utf-8')
    for item in lst:
        stu_txt.write(str(item)+'\n')
    stu_txt.close()

def search():
    student_query=[]
    while True:
        id=''
        name=''
        if os.path.exists(filename):
            mode=input('按id查找请输入1，按姓名查找请按2：')
            if mode=='1':
                id =input("请输入学生id")
            elif mode=='2':
                name =input ('请输入学生姓名')
            else:
                print('您的输入有误，请重新输入')
                search()
            with open(filename,'r',encoding='utf-8') as rfile:
                student=rfile.readlines()
                for item in student:
                    d =dict(eval(item))
                    if id!='':
                        if d['id']==id:
                            student_query.append(d)
                    elif name!='':
                        if d['name']==name:
                            student_query.append(d)
            #显示查询结果
            show_student(student_query)
            #清空列表
            student_query.clear()
            answer = input("是否继续查询？y/n\n")
            if answer == "y" or answer == "Y":
                continue
            else:
                break
        else:
            print('暂未保存学生信息')
            return

def show_student(lst):
    if len(lst)==0:
        print("没有查询到学生信息，无数据显示！")
        return
    #定义标题显示格式
    format_title='{:^6}\t{:^12}\t{:^8}\t{:^10}\t{:^10}\t{:^8}'
    print(format_title.format("id",'姓名',"英语成绩","python成绩","java成绩","总成绩"))
    #定义内容的显示格式
    format_data="{:^6}\t{:^12}\t{:^8}\t{:^10}\t{:^10}\t{:^8}"
    for item in lst:
        print(format_data.format(item.get("id"),
                                 item.get("name"),
                                 item.get("english"),
                                 item.get("python"),
                                 item.get("java"),
                                 int(item.get("english"))+int(item.get("python"))+int(item.get("java"))
                                 ))

def delete():
    while True:
        student_id=input('请输入要删除的学生的id：')
        if student_id!="":
            if os.path.exists(filename):
                with open(filename,'r',encoding="utf-8")as file:
                    student_old=file.readlines()
            else:
                student_old=[]
            flag=False
            if student_old:
                with open(filename,'w',encoding='utf-8') as wfile:
                    d={}
                    for item in student_old:
                        d=dict(eval(item))
                        if d['id']!=student_id:
                            wfile.write(str(d)+'\n')
                        else:
                            flag=True
                    if flag:
                        print(f'id为{student_id}的学生信息已被删除')
                    else:
                        print(f'没有找到ID为{student_id}的学生信息')
            else:
                print('无学生信息')
                break
            show() #删除之后重新显示所有学生
            answer = input("是否继续删除？y/n\n")
            if answer == "y" or answer == "Y":
                continue
            else:
                break

def modify():
    show()
    if os.path.exists(filename):
        with open(filename,'r',encoding='utf-8')as rfile:
            student_old=rfile.readlines()
    else:
        return
    student_id=input("请输入要修改的学生的id：")
    with open(filename,'w',encoding='utf-8')as wfile:
        for item in student_old:
            d=dict(eval(item))
            if d['id']==student_id:
                print('找到学生信息，可以进行相应的修改了')
                while True:
                    try:
                        d["name"]=input("请输入姓名")
                        d['english']=input("请输入英语成绩")
                        d["python"] = input("请输入python成绩")
                        d['java'] = input("请输入java成绩")
                    except:
                        print('您的输入有误，请重新输入')
                    else:
                        break
                wfile.write(str(d)+'\n')
                print("修改成功！")
            else:
                wfile.write(str(d)+'\n')
        answer = input("是否继续修改其他学生信息？y/n\n")
        if answer == "y" or answer == "Y":
            modify()

def sort():
    show()
    if os.path.exists(filename):
        with open(filename,'r',encoding='utf-8')as rfile:
            student_list=rfile.readlines()
        student_new=[]
        for item in student_list:
            d=dict(eval(item))
            student_new.append(d)
    else:
        return
    asc_or_desc=input("请选择（1.升序，2.降序）")
    if asc_or_desc=='0':
        asc_or_desc_bool=True
    elif asc_or_desc=='1':
        asc_or_desc_bool =False
    else:
        print("输入有误，请重新输入！")
        sort()
    mode=input ("请选择排序的方式（1.按english成绩排序 2.按python成绩排序 3.按java成绩排序 0.按总成绩排序）")
    if mode =='1':
        student_new.sort(key=lambda x:int(x['english']),reverse=asc_or_desc_bool)
    elif mode =='2':
        student_new.sort(key=lambda x:int(x['python']),reverse=asc_or_desc_bool)
    elif mode =='3':
        student_new.sort(key=lambda x:int(x['java']),reverse=asc_or_desc_bool)
    elif mode =='0':
        student_new.sort(key=lambda x:int(x['english'])+int(x['python'])+int(x['java']),reverse=asc_or_desc_bool)
    else:
        print ("您的输入有误，请重新输入！")
        sort()
    show_student(student_new)

def total():
    if os.path.exists(filename):
        with open(filename,'r',encoding="utf-8")as rfile:
            students=rfile.readlines()
            if students:
                print("一共有{}名学生".format(len(students)))
            else:
                print("还没有录入学生信息")
    else:
        print("暂未保存数据信息")

def show():
    student_list=[]
    if os.path.exists(filename):
        with open(filename,'r',encoding="utf-8")as rfile:
            students = rfile.readlines()
        for item in students:
            student_list.append(eval(item))
        if student_list:
            show_student(student_list)
    else:
        print("暂未保存数据信息！")

if __name__ == '__main__':
    main()