【作业】工资管理系统

#工资查询
def info_search(usr_name):
    salary = -10000
    with open('info.txt','r') as f:
        for line in f:
            if usr_name==line.split()[0]:
                salary=float(line.split()[1])
                break
    return salary
def info_change(usr_name,salary):
    salary_num=float(salary)
    with open('info.txt', 'r') as f:
        data=f.readlines()
    with open('info.txt','w') as f:
        if salary_num>0:
            f_pos=0
            for line in data:
                if usr_name in line:
                    line=' '.join([usr_name,salary])+'
'
                f.write(line)
            return True
        else:
            return False
def info_add(usr_name,salary):
    if info_search(usr_name)<0:
        with open('info.txt', 'a') as f:
            line='
'+' '.join([usr_name,salary])
            f.write(line)
        return True
    else:
        return False
def Salary_Manager():
    help_info='''
    1. 查询员工工资
    2. 修改员工工资
    3. 增加新员工记录
    4. 退出'''
    while True:
        print(help_info)
        #输入有效性检查
        try:
            usr_select = int(input("请选择(Please select)："))
        except ValueError:
            print('请输入1~4之间的整数。(Please input an integer between 1 and 4.)')
            continue
        if usr_select not in [1,2,3,4]:
            print('请输入1~4之间的整数。(Please input an integer between 1 and 4.)')
            continue
        #查询工资
        if usr_select==1:
            usr_name=input("请输入要查询的员工姓名（例如：Alex）")
            usr_salary=info_search(usr_name)
            if usr_salary>0:
                print("%s的工资是%s"%(usr_name,usr_salary))
            else:
                print('没有找到该员工，请检查。')
        #修改工资
        elif usr_select==2:
            usr_salary=-10000
            items=input('请输入要修改的员工姓名和工资，用空格分隔（例如：Alex 10）：')
            #有效性检查及工资修改
            if len(items.split())==2:
                usr_name=items.split()[0]
                usr_salary=items.split()[1]
                if usr_salary.isnumeric() and float(usr_salary)>0:
                    if info_change(usr_name, usr_salary):
                        print('修改成功。')
                    else:
                        print('输入格式有误或不存该员工。')
                else:
                    print('工资输入有误，请检查。')
            else:
                print('输入格式有误。')

        #增加员工记录
        elif usr_select==3:
            items=input('请输入要增加的员工姓名和工资，用空格分割（例如：Eric 100000）：')
            #有效性检查及人员增加
            if len(items.split())==2:
                usr_name=items.split()[0]
                usr_salary=items.split()[1]
                if usr_salary.isnumeric():
                    if info_add(usr_name, usr_salary):
                        print('增加成功！')
                    else:
                        print('输入格式有误或员工已存在。')
                else:
                    print('工资输入有误，请检查。')
            else:
                print('输入格式有误。')
            pass
        #退出
        else:
            print("再见。Bye.")
            exit()
Salary_Manager()