这个小练手是跟着b站的杨淑娟老师敲的案例附上链接 P135开始https://www.bilibili.com/video/BV1wD4y1o7AS?p=135
首先创建一个stusystem.py和student.txt(txt文件在文件夹中新建）
1、首先，主函数main（）
def main():
while True:
menu()
try: #用try-except是为了以防输入的是无法转换为整型的数据
choice = int(input("请选择："))
if choice in [0,1,2,3,4,5,6,7]:
if choice == 0:
answer = input("您确定要退出系统吗？y/n")
if answer == 'y' or answer == 'Y':
print("您已退出系统！谢谢您的使用！")
break
else:
continue
elif choice == 1:
insert()
elif choice == 2:
search()
elif choice == 3:
delete()
elif choice == 4:
modify()
elif choice == 5:
sort()
elif choice == 6:
total()
elif choice == 7:
show()
else:
print("输入错误，请重新输入！")
continue
except: #若输入的无法用int转换，则执行except的内容
print("您输入的有误，请重新输入！")
continue
以及菜单显示函数
def menu():
print("========================学生信息管理系统==========================")
print("—————————————————————————————功能菜单—————————————————————————————")
print("\t\t\t\t\t\t1.录入学生信息")
print("\t\t\t\t\t\t2.查找学生信息")
print("\t\t\t\t\t\t3.删除学生信息")
print("\t\t\t\t\t\t4.修改学生信息")
print("\t\t\t\t\t\t5.排序")
print("\t\t\t\t\t\t6.统计学生总人数")
print("\t\t\t\t\t\t7.显示所有学生信息")
print("\t\t\t\t\t\t0.退出系统")
print("——————————————————————————————————————————————————————————————————")
2、录入学生信息功能
def insert():
student_lst = []
while True:
id = input("请输入ID（如1001）：")
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: #如果不能转换成int类型，就会转为执行except的语句
print("输入无效，不是整数类型，请重新输入！")
continue
#将录入的学生信息保存到字典中
student = {'id':id,'name':name,'english':english,'python':python,'java':java}
#将学生信息添加到列表中
student_lst.append(student)
answer = input("是否继续添加？y/n")
if answer == 'y' or answer == 'Y':
continue
else:
break
#调用save()函数
save(student_lst)
print("学生信息录入完毕！")
save（）保存信息函数
def save(lst):
try:
stu_txt = open(filename,'a',encoding='utf-8') #如果文件存在，就用追加的方式，a是以追加的模式打开，utf-8是为了防止中文乱码
except: #如果不存在，就以写入的模式
stu_txt = open(filename,'w',encoding='utf-8')
for item in lst: #item可以是字典
stu_txt.write(str(item)+'\n') #将字典的内容转换成字符串保存
stu_txt.close()
3、查询学生信息功能
def search():
student_query = []
while True:
id = ''
name = ''
if os.path.exists(filename):
mode = input("按ID查询请输入1，按姓名查询请输入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("输入有误！请重新输入！")
search()
with open(filename,'r',encoding='utf-8') as rfile:
student = [line.strip() for line in rfile.readlines() if line.strip()]
for item in student:
d = dict(eval(item))
if id != '':
if d['id'] == id:
student_query.append(d)
if name != '':
if d['name'] == name:
student_query.append(d)
#显示查询结果
show_student(student_query)
#清空查询列表
student_query.clear()
answer = input("是否继续查询？y/n")
if answer == 'y':
continue
else:
break
else:
print("无学生信息！")
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
#定义标题格式
format_title = '{:^6}\t{:^12}\t{:^8}\t{:^10}\t{:^10}\t{:^10}' #^6表示居中，宽度为6
print(format_title.format('ID','姓名','英语成绩','python成绩','java成绩','总成绩'))
format_data = '{:^6}\t{:^12}\t{:^10}\t{:^10}\t{:^10}\t{:^12}'
for item in lst:
print(format_data.format(item['id'],
item['name'],
item['english'],
item['python'],
item['java'],
int(item['english'])+int(item['python'])+int(item['java'])))
4、删除学生信息功能
def delete():
while True:
student_id = input("请输入要删除的学生ID：")
if student_id != '':
if os.path.exists(filename): #如果filename存在
with open(filename,'r',encoding='utf-8') as rfile:
student_old = [line.strip() for line in rfile.readlines() if line.strip()] #将读取的数据存入student_old
else:
student_old = []
flag = False
#开始找要删除的学生信息
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"抱歉！未找到ID为{student_id}的学生信息！")
else:
print("抱歉！暂无学生信息！")
show() #显示删除完信息后的表格
answer = input("是否继续删除？y/n")
if answer == 'y' or answer == 'Y':
continue
else:
break
5、修改学生信息功能
def modify():
show()
if os.path.exists(filename):
with open(filename,'r',encoding='utf-8') as rfile:
student_old = [line.strip() for line in rfile.readlines() if line.strip()]
else:
return
student_id = input("请输入需要修改信息的学生ID：")
if student_id != '':
with open(filename,'w',encoding='utf-8') as wfile:
d = {}
for item in student_old:
d = dict(eval(item)) #将字符串转成字典类型
if d['id'] == student_id:
print("找到学生！可以进行修改！")
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("输入有误！请重新输入！")
else:
break
wfile.write(str(d)+'\n')
print("学生信息已修改成功！")
else:
wfile.write(str(d)+'\n')
answer = input("是否继续修改学生信息？y/n")
if answer == 'y' or answer == 'Y':
modify()
7、排序模块设计
def sort():
show()
if os.path.exists(filename):
with open(filename,'r',encoding='utf-8') as rfile:
students = [line.strip() for line in rfile.readlines() if line.strip()]
student_new = []
for item in students:
d = dict(eval(item))
student_new.append(d)
asc_or_desc = input("请选择排序方式（0.升序 1.降序）：")
if asc_or_desc == '0' :
asc_or_desc_bool = False
elif asc_or_desc == '1':
asc_or_desc_bool = True
else:
print("您的输入有误。请重新输入。")
sort()
mode = input("请选择（1.按英语成绩排序 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)
else:
print("暂未保存学生信息...")
8、统计学生总人数
def total():
if os.path.exists(filename):
with open(filename,'r',encoding='utf-8') as rfile:
student = [line.strip() for line in rfile.readlines() if line.strip()]
if student:
print(f"一共有{len(student)}名学生")
else:
print("无学生信息！")
else:
print("暂未录入学生信息...")
9、显示所有学生信息功能
def show():
student_lst = []
if os.path.exists(filename):
with open(filename,'r',encoding='utf-8') as rfile:
student = [line.strip() for line in rfile.readlines() if line.strip()]
for item in student:
student_lst.append(eval(item))
if student_lst:
show_student(student_lst)
else:
print("暂未录入学生信息...")
10、运行主函数
if __name__ == '__main__':
main()