就是学生管理系统中的students怎么定义
s = "姓名:%s,年龄:%d，分数:%2f"
name = input("请输入名字:")
age = int(input("请输入年龄:"))
score = int(input("请输入分数;"))
print(s % (name,age,score))

将学生信息进行打印

title1 = '+' + '-' * 15 + '+' + '-' * 5 + '+' + '-' * 7 + '+'
title2 = '|%s|%s|%s|' % ('name'.center(15),'age'.center(5),'score'.center(7))
print(title1)
print(title2)
print(title1)
for stu in students:
print('|%s|%s|%s|' % (
stu['name'].center(15),

从字典里面去除姓名和分数，转为字符串并居中，然后格式化填入

    str(stu['age']).center(5),
    str(stu['score']).center(7)
))

print(title1)

修改学生数据

def modify_students(students):
name = input("请输入要修改的学生名字:")
# students [{"name":"zs","age":19,...},()]
for stu in students:
if name == stu['name']:
score = int(input("请输入你要修改的成绩:"))
stu['score'] = score
print("修改%s的成绩成功" % name)
return
print("没有找到名字为%s的学生，修改失败" % name)

修改学生数据

def delete_students(students):
name = input("请输入要删除的学生名字:")
for stu in students:
if name == stu['name']:
students.remove(stu)
print("删除名为%s的学生成功" % name)
return
print("没有名为%s的学生，删除失败")

部分主函数参考代码

def main():
stu_infos = []
while True:
show_menu()
op = input("请选择:")
if op == '1':
students = input_student()
stu_infos.extend(students)
elif op == '2':
output_student(stu_infos)
elif op == '3':
modify_students(stu_infos)
elif op =='4':
delete_students(stu_infos)
elif op =='0':
print("退出程序")
return
else:
print("输入不正确")
p = input("请输入y回主菜单，输入其他退出程序")
if p !='y':
print("退出程序")
print("输入不正确")
p = input("输入y回主菜单，输入其它退出程序")
if p !='y':
print("退出程序")
return

if name == "nain":
main()

将students定义为一个元素为字典的列表即可，代码修改如下：

def input_students():
    students = []
    s = "姓名:%s,年龄:%d，分数:%2f"
    name = input("请输入名字:")
    age = int(input("请输入年龄:"))
    score = int(input("请输入分数:"))
    print(s % (name,age,score))
    students.append({'name':name,'age':age,'score':score})
    return students
def output_students(students):
    title1 = '+' + '-' * 15 + '+' + '-' * 5 + '+' + '-' * 7 + '+'
    title2 = '|%s|%s|%s|' % ('name'.center(15),'age'.center(5),'score'.center(7))
    print(title1)
    print(title2)
    print(title1)
    for stu in students:
        print('|%s|%s|%s|' % (
        stu['name'].center(15),str(stu['age']).center(5),str(stu['score']).center(7)))
    print(title1)
#修改学生数据
def modify_students(students):
    name = input("请输入要修改的学生名字:")
    # students [{"name":"zs","age":19,...},()]
    for stu in students:
        if name == stu['name']:
            score = int(input("请输入你要修改的成绩:"))
            stu['score'] = score
            print("修改%s的成绩成功" % name)
        return
    print("没有找到名字为%s的学生，修改失败" % name)

#修改学生数据
def delete_students(students):
    name = input("请输入要删除的学生名字:")
    for stu in students:
        if name == stu['name']:
            students.remove(stu)
            print("删除名为%s的学生成功" % name)            
            return students
        print("没有名为%s的学生，删除失败")
def show_menu():
    print('######学生成绩管理系统######\n')
    print('1.输入学生信息\n2.输出学生信息\n3.修改学生信息\n4.删除学生信息\n5.退出系统')
    print('############################\n')
#部分主函数参考代码
def main():
    stu_infos = []
    while True:
        show_menu()
        op = input("请选择:")
        if op == '1':
            students = input_students()
            stu_infos.extend(students)
        elif op == '2':
            output_students(stu_infos)
        elif op == '3':
            modify_students(stu_infos)
        elif op =='4':
            delete_students(stu_infos)
        elif op =='5':
            print("退出程序")
            break        
        else:
            print("输入不正确")
            p = input("请输入y回主菜单，输入其他退出程序")
            if p !='y':
                print("退出程序")
                print("输入不正确")
                p = input("输入y回主菜单，输入其它退出程序")
            if p !='y':
                print("退出程序")

if __name__ == "__main__":
    main()

就你的代码来看，就包括3个字段，name,age,score