Python-流程控制之循環

# 1. while循環：條件循環# I:基本語法# while 條件：#     代碼1#     代碼2#     代碼3#     ...# 示範# name_of_bk='huangdong'# paw_of_bk='123'## tag=True# while tag:#     inp_name=input('your name>>:')#     inp_pwd=input('your password>>:')#     if inp_name == name_of_bk and inp_pwd == paw_of_bk:#         print('login successful')#         tag=False#     else:#         print('username or password error')##     print('emmmmmm')# II: while+break:break表明結束本層循環# 示範：# while True:#     print(1)#     break#     print(2)#     print(3)# name_of_bk='huangdong'# paw_of_bk='123'## while True:#     inp_name=input('your name>>:')#     inp_pwd=input('your password>>:')#     if inp_name == name_of_bk and inp_pwd == paw_of_bk:#         print('login successful')#         break#     else:#         print('username or password error')##     print('emmmmmm')# III: while + continue: continue表明結束本次循環，直接進入下一次# 示範# count=1# while count <6:#     if count == 3:#         count+=1#         continue#     print(count)#     count+1# 輸錯三次退出# name_of_bk='huangdong'# paw_of_bk='123'## count=0# while True:#     if count == 3:#         print('輸錯次數過多..')#         break#     inp_name=input('your name>>:')#     inp_pwd=input('your password>>:')#     if inp_name == name_of_bk and inp_pwd == paw_of_bk:#         print('login successful')#         break#     else:#         print('username or password error')#         count+=1 #count=3 輸錯3次###     print('emmmmmm')# IV:while + else# count=0# while True:#     if count == 10:#         break#     print(count)#     count+=1# else:#     print('else的子代碼塊只有在while循壞沒有被break打斷的狀況下才會執行')# count=0# while count <= 10:#     print(count)#     count+=1## else:#     print('else的子代碼塊只有在while循壞沒有被break打斷的狀況下才會執行')name_of_bk='huangdong'pwd_of_bk='123'count=0tag=Truewhile tag:    if count == 3:        print('輸錯次數過多...')        break    inp_name=input('your name>>:')    inp_paw=input('your password>>:')    if inp_name == name_of_bk and inp_paw == inp_paw:        print('login password')        while tag:            print('''            0 退出            1 購物            2 支付            3 查看購物車            ''')            cmd=input('>>:')            if cmd == '0':                tag=False                continue            if cmd == '1':                print('購物...')            elif cmd =='2':                print('支付..')            elif cmd == '3':                print('購物車')            else:                print('輸入錯誤的指令')    else:        print('username or password error')