PYTHON-字符編碼&文件處理-練習

# 把多個帳號密碼寫入文件中# 編寫登陸功能，登陸失敗三次 程序退出。# 登陸帳號密碼定義，用列表分割，for循環取值=====判斷對錯=====循環條件3次退出# with open(r'db.txt',mode='r') as f:#     db=f.read().split('|')#     # print(db)#     z=[]#     for x in db:#         y=x.split(':')#         # print(y)#         count=0#         z.append(y)#     print(z)#     while True:#         usr = input('username')#         pwd = input('password')#         if usr == z[0][0] and pwd == z[0][1]:#             print('login in')#             break#         else:#             print('error')#             count+=1#         if count>=3:#             print('blocked')#             break    # for x in db:    #     z = x.split(':')    #     z.append(y)    #     count = 0    # while True:    #     usr = input('username')    #     pwd = input('password')    #     zz=[usr,pwd]    #     if zz in y:    #         print('login in')    #         break    #     else:    #         print('error')    #         count += 1    #     if count >= 3:    #         print('blocked')    #         break# 1. 文件db2.txt內容：每一行內容分別爲商品名字，價錢，個數，求出本次購物花費的總錢數# apple 10 3# tesla 100000 1# mac 3000 2# lenovo 30000 3# chicken 10 3ttl=0count=0with open(r'db2.txt',mode='r') as f:    db=f.read().split('\n')    # print(db)    for x in db:        y=x.split(' ')        # print(y)        ttl+=int(y[1])*int(y[2])        count+=1        if count < 5:            continue        print(ttl)