day07__while_and_break
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# 2、死循环与效率问题 # count=0 # while count < 5: # 5 < 5 # print(count) # 0,1,2,3,4 # while True: # name=input('your name >>>> ') # print(name) # 纯计算无io的死讯会导致致命的效率问题 # while True: # 1+1 # 4、退出循环的两种方式 # 方式一:将条件改为False,等到下次循环判断条件时才会生效 # tag=True # while tag: # inp_name=input('请输入您的账号:') # inp_pwd=input('请输入您的密码:') # # if inp_name == username and inp_pwd == password: # print('登录成功') # tag = False # 之后的代码还会运行,下次循环判断条件时才生效 # else: # print('账号名或密码错误') # # # print('====end====') # 每一层都必须配一个break while True: while True: while True: break break break # 8、while +continue:结束本次循环,直接进入下一次 # 强调:在continue之后添加同级代码毫无意义,因为永远无法运行 # count=0 # while count < 6: # if count == 4: # count+=1 # continue # # count+=1 # 错误 # print(count) # count+=1 # 9、while +else:针对break # count=0 # while count < 6: # if count == 4: # count+=1 # continue # print(count) # count+=1 # else: # print('else包含的代码会在while循环结束后,并且while循环是在没有被break打断的情况下正常结束的,才会运行') # 应用案列: # 版本1: # count=0 # tag=True # while tag: # if count == 3: # print('输错三次退出') # break # inp_name=input('请输入您的账号:') # inp_pwd=input('请输入您的密码:') # # if inp_name == username and inp_pwd == password: # print('登录成功') # while tag: # cmd=input("输入命令>: ") # if cmd == 'q': # tag=False # else: # print('命令{x}正在运行'.format(x=cmd)) # else: # print('账号名或密码错误') # count+=1 # 版本2:优化 # count = 0 # while count < 3: # inp_name = input('请输入您的账号:') # inp_pwd = input('请输入您的密码:') # # if inp_name == username and inp_pwd == password: # print('登录成功') # while True: # cmd = input("输入命令>: ") # if cmd == 'q': # 整个程序结束,退出所有while循环 # break # else: # print('命令{x}正在运行'.format(x=cmd)) # break # else: # print('账号名或密码错误') # count += 1 # else: # print('输错3次,退出')