Python 实现购物商城,含有用户入口和商家入口的示例

# Joe Youngimport getpassimport os# 调用os模块的system方法传入'cls'参数，清屏os.system('cls') while True: entrance = input('请选择：/n/t1. 用户登陆/n/t2. 商家登陆/n>>>') if entrance != '1' and entrance != '2':  print('/n输入有误，请重试.../n') else:  break# 打印商品列表def print_product_list(): index = 1 with open('product_list.txt', 'r') as product_file:  for product_line in product_file:   L = [commodity, price, stock] = product_line.strip('/n').split(', ')   commodity_list.append(L)   print((str(index) + '. ' + commodity).ljust(20) + ('单价：' + price + '元').ljust(15) + '库存：' + stock)   index += 1 return# 用户入口if entrance == '1': info = []   # 存放用户的信息，初始为空 if_payed = True # if_payed 表示订单是否已支付 username = '' # 登录接口 count = 0 while count < 3:  username = input('/n用户名： ')  # 打开锁定列表文件  with open('lock_list.txt', 'r+') as lock_file:    for lock_line in lock_file:    # 用户名在锁定名单里面，则退出程序    if username == lock_line.strip('/n'):      exit('/n用户名 %s 已被锁定，请联系管理员...' % username)  login = False # 登录标志，初始为False  # 打开用户名列表文件，读权限  user_file = open('user_list.txt', 'r')    for user_line in user_file:   # 获取每行的用户信息，用户名、密码、余额、支付密码，存入info列表   info = [user, passwd, balance, pay_passwd] = user_line.strip('/n').split(',')   # 用户名匹配，则进入密码输入环节   if user == username:     n = 0    # 3次输入机会    while n < 3:      password = getpass.getpass('密码： ')     # 密码匹配，显示登录成功     if passwd == password:       print('/n欢迎 %s 登录商城，祝您购物愉快！/n' % username)      login = True  # 登录标志赋值为True      break     # 密码不匹配     else:       # n = 2 时是最后一次机会，不必提示还剩下0次机会      if n != 2:        print('/n密码错误，请重新输入，您还有 %d 次机会/n' % (2-n))     n += 1    # 密码错误次数达到3次，锁定用户名，退出程序    else:      open('lock_list.txt', 'w').write(username + '/n')     exit('/n错误次数过多，账户已被锁定...')    # 登录成功，跳出for循环    if login:      break  else:   if count != 2:    print('/n用户名不存在，请重试，您还有 %d 次机会' % (2-count))  user_file.close()  count += 1  # 登录成功，跳出while循环  if login:    break else:  exit('/n错误次数过多，程序已退出...') # 购买程序 shopping_cart = [] # 购物车初始为空 commodity_list = [] print_product_list() while True:  i = input('/n请选择商品（输入序号），或输入 c 取消购买：')  if i == 'c':   while True:    a = input('/n是否继续购买？（Y/N）:')    if a == 'n' or a == 'N':     exit('/n交易结束...')    elif a == 'y' or a == 'Y':     break    else:     print('/n输入格式有误，请重试...')     continue  if not i.isdigit():   print('/n输入格式有误，请重试...')   continue  i = int(i)  if i <= 0 or i > len(commodity_list):   print('/n此商品不存在，请重试...')   continue  item_name = commodity_list[i-1][0]  # 商品名称  item_price = commodity_list[i-1][1]  # 商品价格  item_stock = commodity_list[i-1][2]  # 商品库存  print('/n您已选择了 %s ，请输入购买的数量，或输入 b 重新选择：' % item_name)  back = False  while True:   num = input('>>>')   if num == 'b':    back = True    break   if not num.isdigit():    print('输入格式有误，请重试...')    continue   if int(num) > int(item_stock):    print('数量大于库存，请重试...')    continue   if int(num) == 0:    print('数量应大于0，请重试...')   break  if back:   continue  item = [item_name, item_price, num]  print('/n您已选择了 %s，单价：%s 元，数量：%s，您想立即购买还是加入购物车？/n' % (item_name, item_price, num))  print('/t1. 立即购买/n/t2. 加入购物车/n')  while True:   choice = input('>>>')   if not (choice == '1' or choice == '2'):    print('输入有误，请重试...')    continue   break  user_balance = int(info[2])  # 立即购买  if choice == '1':    amount = int(item_price) * int(num)   count = 0   cancel = False   while count < 3:    user_pay_passwd = getpass.getpass('/n请输入支付密码，或输入 c 放弃支付：')    if user_pay_passwd == 'c':     print('/n取消支付成功...')     cancel = True     break    elif user_pay_passwd != info[3]:     if count != 2:      print('/n密码错误，请重试，您还有 %d 次机会...' % (2-count))     count += 1    else:     break   if count == 3:    with open('lock_list.txt', 'w') as lock_file:     lock_file.write(username + '/n')    exit('密码错误，账户已被锁定...')   if cancel:    while True:     choice = input('/n是否继续购买？(Y/N)：')     if not (choice == 'Y' or choice == 'y' or choice == 'N' or choice == 'n'):      print('/n输入格式有误，请重试...')      continue     break    if choice == 'Y' or choice == 'y':     continue    else:     break   # 如果用户的账户余额大于总金额   if user_balance >= amount:     user_balance -= amount    print('/n支付成功！您已成功购买 %s ，单价：%s 元，数量：%s，总金额：%s 元，账户余额：%s 元'      % (item_name, item_price, num, amount, user_balance))    lines = open('product_list.txt', 'r').readlines()    # 定位到用户所购买的商品所在行，分割成列表赋值给select    select = lines[i-1].strip('/n').split(', ')        # 修改商品的库存    select[-1] = (str(int(select[-1]) - int(num)) + '/n')     # 拼接成字符串    lines[i-1] = ', '.join(select)           # 将修改写回文件    open('product_list.txt', 'w').writelines(lines)       lines = open('user_list.txt', 'r').readlines()    # 修改用户余额    for line in lines:      if username in line.split(','):  # 定位到用户名所在行      j = lines.index(line)   # 获取用户名所在行的行号索引      select = line.split(',')  # 分割用户名所在行赋值给列表select      select[-2] = str(user_balance) # 修改用户余额      lines[j] = ','.join(select)  # 修改后的列表拼接成字符串，覆盖用户名所在行      open('user_list.txt', 'w').writelines(lines) # 将修改写回文件   else:    print('/n对不起，您的余额不足...')  else: # 加入购物车   j = 0   for j in range(len(shopping_cart)):    # 如果商品在购物车里面，更新商品数量    if item_name in shopping_cart[j]:      shopping_cart[j][2] = str(int(shopping_cart[j][2]) + int(num))     break   # 商品若不在购物车，则添加到购物车   else:    shopping_cart.append(item)    print('/n成功加入购物车！')  while True:   choice = input('/n是否继续购买？(Y/N)：')   if not (choice == 'Y' or choice == 'y' or choice == 'N' or choice == 'n'):    print('/n输入格式有误，请重试...')    continue   break  if choice == 'Y' or choice == 'y':   continue  else:   break # 如果购物车不为空 if shopping_cart:   print('/n您的购物车里有以下宝贝：/n')  i = 1  total_sum = 0  for item in shopping_cart:   (commodity, price, number) = (item[0], item[1], item[2])   print((str(i) + '. ' + commodity).ljust(20) + ('单价：' + price + ' 元').ljust(15) + '数量：' + number)   total_sum += int(price) * int(number)   i += 1  print('/n合计：%d 元' % total_sum)  while True:   if_buy = input('/n是否结算？(Y/N):')   if not (if_buy == 'Y' or if_buy == 'y' or if_buy == 'N' or if_buy == 'n'):    print('/n输入有误，请重试...')    continue   break  while True:   # 结算   if if_buy == 'Y' or if_buy == 'y':     count = 0    cancel = False    while count < 3:     user_pay_passwd = getpass.getpass('/n请输入支付密码，或输入 c 放弃支付：')     if user_pay_passwd == 'c':      print('/n取消支付成功...')      cancel = True      break     elif user_pay_passwd != info[3]:      if count != 2:       print('/n密码错误，请重试，您还有 %d 次机会...' % (2-count))      count += 1     else:      break    if cancel:     if_payed = False    elif count == 3:     with open('lock_list.txt', 'w') as lock_file:      lock_file.write(username + '/n')     exit('/n密码错误，账户已被锁定...')    else:     if total_sum <= user_balance:      user_balance -= total_sum      print('/n支付成功！您已成功购买以下商品：/n')      i = 1      for item in shopping_cart:       (commodity, price, number) = (item[0], item[1], item[2])       print((str(i) + '. ' + commodity).ljust(20) +         ('单价：' + price + ' 元').ljust(15) + '数量：' + number)       lines = open('product_list.txt', 'r').readlines()       for line in lines: # 修改商品库存        if commodity in line.split(', '):     # 定位到商品所在行         j = lines.index(line)       # 获取商品所在行的行号索引         select = line.split(', ')      # 商品所在行分割为字符串列表         select[-1] = (str(int(select[-1]) - int(number)) + '/n') # 修改商品库存         lines[j] = ', '.join(select)      # 将修改后的字符串列表组成字符串         open('product_list.txt', 'w').writelines(lines) # 把修改写回文件       i += 1      lines = open('user_list.txt', 'r').readlines()      for line in lines: # 用户余额写入文件       if username in line.split(','):        j = lines.index(line)        select = line.split(',')        select[-2] = str(user_balance)        lines[j] = ','.join(select)        open('user_list.txt', 'w').writelines(lines)      exit('/n合计：%d 元， 账户余额：%d 元' % (total_sum, user_balance))   # 不结算   else:     print('/n您有一笔未支付订单...')    while True:     choice = input('/n是否进行支付？(Y/N):')     if not (choice == 'Y' or choice == 'y' or choice == 'N' or choice == 'n'):      print('/n输入有误，请重试...')      continue     break    if choice == 'n' or choice == 'N':     exit('/n订单已取消，感谢光临购物商城，再见...')    else:     if_buy = 'Y'     continue   if not if_payed:    print('/n您有一笔未支付订单...')    while True:     choice = input('/n是否进行支付？(Y/N):')     if not (choice == 'Y' or choice == 'y' or choice == 'N' or choice == 'n'):      print('/n输入有误，请重试...')      continue     break    if choice == 'n' or choice == 'N':     exit('/n订单已取消，感谢光临购物商城，再见...')    else:     if_buy = 'Y'     continue# 商家入口if entrance == '2':   seller_name = '' # 登录接口 count = 0 while count < 3:  seller_name = input('/n用户名：')  with open('lock_list.txt', 'r') as lock_file:   for lock_line in lock_file:    if seller_name == lock_line.strip('/n'):     exit('/n用户名 %s 已被锁定，请联系管理员...' % seller_name)  seller_file = open('seller_list.txt', 'r')  login = False  for seller_line in seller_file:   (seller, passwd) = seller_line.strip('/n').split(',')   if seller_name == seller:    n = 0    while n < 3:     password = getpass.getpass('密码：')     # 登录成功，跳出while循环     if password == passwd:      print('/n欢迎 %s 登录商城' % seller_name)      login = True      break      else:      if n != 2:       print('/n密码错误，请重试，您还有 %d 次机会' % (2-n))     n += 1    # n = 3，锁定用户名    else:        open('lock_list.txt', 'w').write(seller_name + '/n')     exit('/n错误次数过多，账户已被锁定...')    # 登录成功，跳出for循环    if login:       break  # 用户名不存在  else:     if count != 2:    print('/n用户名不存在，请重试，您还有 %d 次机会' % (2-count))  # 登录成功，跳出while循环  if login:    break  count += 1 else:  exit('/n错误次数过多，程序已退出...') # 商品列表编辑程序  L = [] # 存放商品列表，初始为空 commodity_list = [] index = 1 print('/n您的货架上有以下商品：/n')  print_product_list() while True:  choice = input('/n是否编辑您的商品列表？(Y/N):')  if not (choice == 'Y' or choice == 'y' or choice == 'N' or choice == 'n'):   print('/n输入有误，请重试...')   continue  break if choice == 'Y' or choice == 'y':  while True:   print('/n请选择（输入 q 退出）：/n')   print('1. 上架新品/n/n2. 下架商品/n/n3. 修改商品信息')   choice = input('/n>>>')   if not (choice == '1' or choice == '2' or choice == '3' or choice == 'q'):    print('输入有误，请重试...')    continue   # 上架新品   if choice == '1':    while True:     if_add = False # 是否添加商品的标志，初始为False     new_commodity = input('/n输入商品名：')     product_file = open('product_list.txt', 'r')     for product_line in product_file:      commodity = product_line.strip('/n').split(', ')[0]  # 获取商品列表中的商品名      if new_commodity == commodity:       print('/n此商品已在货架上...')       continue      else:       while True:        if_sure = input('/n确定上架新品 %s 吗？（Y/N）：' % new_commodity)        if not (if_sure == 'Y' or if_sure == 'y' or if_sure == 'N' or if_sure == 'n'):         print('/n输入有误，请重试...')         continue        break       # 确定上架新品       if if_sure == 'Y' or if_sure == 'y':        while True:  # 输入单价         price = input('/n请输入单价：')         if not price.isdigit():          print('/n输入有误，请重试...')          continue         break        while True:  # 输入库存         stock = input('/n请输入库存：')         if not stock.isdigit():          print('/n输入有误，请重试...')          continue         break        new_line = '/n' + new_commodity + ', ' + price + ', ' + stock        open('product_list.txt', 'a').writelines(new_line)        print('/n成功上架新品 %s ,单价 %s 元，库存 %s 件' % (new_commodity, price, stock))        while True:         option = input('/n是否继续添加？(Y/N):')         if not (option == 'Y' or option or option == 'N' or option == 'n'):          print('/n输入有误，请重试...')          continue         break        if option == 'Y' or option == 'y':         if_add = True         break # 跳出for循环        else:         break       # 取消上架新品       else:        if_add = False        break # 跳出for循环     product_file.close()     if if_add is True:      continue     else:      break # 跳出while循环   # 下架商品   elif choice == '2':    while True:     del_num = input('/n请输入您想下架商品的序号：')     if not (del_num.isdigit() or int(del_num) > 0 and int(del_num) <= len(commodity_list)):      print('/n输入有误，请重试...')      continue     break    del_num = int(del_num)    del_commodity = commodity_list[del_num - 1][0]    with open('product_list.txt', 'r') as old_file:     with open('product_list.txt', 'r+') as new_file:      current_line = 0      # 定位到需要删除的行      while current_line < (del_num - 1):       old_file.readline()       current_line += 1      # 当前光标在被删除行的行首，记录该位置      seek_point = old_file.tell()      # 设置光标位置      new_file.seek(seek_point, 0)      # 读需要删除的行，光标移到下一行行首      old_file.readline()            # 被删除行的下一行读给 next_line      next_line = old_file.readline()      # 连续覆盖剩余行，后面所有行上移一行      while next_line:       new_file.write(next_line)       next_line = old_file.readline()      # 写完最后一行后截断文件，因为删除操作，文件整体少了一行，原文件最后一行需要去掉      new_file.truncate()    print('/n您已成功下架 %s ！' % del_commodity)   # 修改商品信息   elif choice == '3':    # 修改商品信息    def mod_commodity_info(i, j):     i = int(i)     j = int(j)     with open('product_list.txt', 'r+') as f:      current_line = 0      while current_line < i - 1:       f.readline()       current_line += 1      seek_point = f.tell()      f.seek(seek_point, 0)      # 修改商品名      if j == 1:       update_line = mod_name() + ', ' + commodity_list[i-1][1] + ', ' + commodity_list[i-1][2] + '/n'      # 修改商品价格      elif j == 2:       update_line = commodity_list[i-1][0] + ', ' + mod_price() + ', ' + commodity_list[i-1][2] + '/n'      # 修改商品库存      else:       update_line = commodity_list[i-1][0] + ', ' + commodity_list[i-1][1] + ', ' + mod_stock() + '/n'            f.write(update_line)     return        def mod_name():     new_name = input("/n请输入新的商品名：")     return new_name    def mod_price():     new_price = input("/n请输入新的商品单价：")     return new_price    def mod_stock():     new_stock = input("/n请输入新的商品库存：")     return new_stock    # 修改商品单价    def mod_commodity_price(i):     i = int(i)     with open('product_list.txt', 'r+') as f:      current_line = 0      while current_line < i -1:       f.readline()       current_line += 1      seek_point = f.tell()      f.seek(seek_point, 0)      new_price = input()    while True:     i = input("/n请输入需要编辑的商品序号（输入 c 取消）：")     if not (i.isdigit or i == 'c' or int(i) > 0 and int(i) <= len(commodity_list)):      print("/n输入有误，请重试...")      continue     elif i == 'c':      break     else:      while True:       j = input("/n请选择需要编辑的选项（输入 c 取消）：/n/n1. 商品名/n/n2. 单价/n/n3. 库存/n/n>>>")       if not (j == 'c' or j == '1' or j == '2' or j == '3'):        print("/n输入有误，请重试...")        continue       break      if j == 'c':       break      else:       mod_commodity_info(i, j)   else:    exit('/n您已退出商城...') else:  exit('/n您已退出商城...')