一、 从第3层循环直接跳出所有循环
break_flag = False
count = 0
while break_flag == False:
print("-第一层")
while break_flag == False:
print("第二层")
while break_flag == False:
count += 1
if count > 10:
break_flag = True
print("第三层")
print("keep going...")
# break_flag = False
count = 0
while count < 3:
print("-第一层")
while count < 3:
print("第二层")
while count <= 10:
count += 1
# if count > 10:
# break_flag = True
print("第三层")
print("keep going...")
二、 购物车程序
goods_list = [['Iphone7',5800],['Coffee',30],['Book',99],['Bike',199],['Vivi X9',2499]] #商品列表
shopping_cart = [] #用户购物车列表
salary = int(input('input your salary:')) #用户薪水
m = salary
k = 0
while True:
index = 0
for goods in goods_list: #打印商品列表
print(index,goods)
index += 1
choice = input('>>>:').strip()
if choice.isdigit():
choice = int(choice)
if choice >= 0 and choice < len(goods_list):
goods = goods_list[choice]
if goods[1] <= salary: #判断用户是否带了足够的钱来支付所选商品
shopping_cart.append(goods)
salary -= goods[1]
print('Add goods '+str(goods[0])+' into shopping cart! Your current balance:'+str(salary))
else:
print('No enough money!The price is:'+str(goods[1])+'! Need more:'+str(goods[1]-salary))
else:
print('Have no this goods!')
elif choice == 'q':
print('----------Your shopping cart----------')
print('ID goods quantity price total')
for i in range(len(goods_list)):
j = shopping_cart.count(goods_list[i])
if j > 0 :
k += 1
print(k,'\t',goods_list[i][0],'\t',j,'\t\t',goods_list[i][1],'\t',j * goods_list[i][1])
print('Total price is:',m - salary)
break
else:
print('Have no this goods')
goods_list = [['Iphone7',5800],['Coffee',30],['Book',99],['Bike',199],['Vivi X9',2499]] # 商品列表
shopping_cart = {} # 用户购物车列表从列表变为字典
salary = int(input('input your salary:')) # 用户薪水
# m = salary #不需要此项
# k = 0 #用户购物车商品打印ID，移动位置至打印循环外
while True:
index = 0
for goods in goods_list: # 打印商品列表
print(index, goods)
index += 1
choice = input('>>>:').strip()
if choice.isdigit(): # 判断是否为数字
choice = int(choice)
if choice >= 0 and choice < len(goods_list): # 商品存在
goods = goods_list[choice]
if goods[1] <= salary: # 判断用户是否带了足够的钱来支付所选商品
if goods[0] in shopping_cart: # 之前买过
shopping_cart[goods[0]][1] += 1 # 购物数量加1
else:
shopping_cart[goods[0]] = [goods[1], 1] # 创建一条新增商品的购买记录
salary -= goods[1] # 扣钱
print('Add goods ' + str(goods[0]) + ' into shopping cart! Your current balance:' + str(salary))
else:
print('No enough money!The price is:' + str(goods[1]) + '! Need more:' + str(goods[1] - salary))
else:
print('Have no this goods!')
elif choice == 'q':
id_counter = 1 # 初始化商品ID
total_cost = 0 # 初始化商品总花费
print('----------Your shopping cart----------')
print('ID goods quantity price total')
for i in shopping_cart:
print("%-5s%-10s%-12s%-10s%-s"
% (
id_counter, i, shopping_cart[i][1], shopping_cart[i][0],
shopping_cart[i][0] * shopping_cart[i][1]))
id_counter += 1 # 商品ID自加1
total_cost += shopping_cart[i][0] * shopping_cart[i][1] # 用户已购商品总花费
print('Total price is:', total_cost)
break
else:
print('Have no this goods')三、多级菜单
要求:
- 打印省、市、县三级菜单
- 可返回上一级（b，返回）
- 可随时退出程序（q，退出）
menu = {
'北京':{
'海淀':{
'五道口':{
'soho':{},
'网易':{},
'google':{}
},
'中关村':{
'爱奇艺':{},
'汽车之家':{},
'youku':{},
},
'上地':{
'百度':{},
},
},
'昌平':{
'沙河':{
'老男孩':{},
'北航':{},
},
'天通苑':{},
'回龙观':{},
},
'朝阳':{},
'东城':{},
},
'上海':{
'闵行':{
"人民广场":{
'炸鸡店':{}
}
},
'闸北':{
'火车战':{
'携程':{}
}
},
'浦东':{},
},
'山东':{},
}
exit_flag = False
current_layer = menu
layers = [menu]
while not exit_flag:
for k in current_layer:
print(k)
choice = input(">>:").strip()
if choice == "b":
current_layer = layers[-1]
#print("change to laster", current_layer)
layers.pop()
elif choice == 'q':
break
elif choice not in current_layer:
continue
else:
layers.append(current_layer)
current_layer = current_layer[choice]四、用户登陆程序
需求：
- 最多允许用户尝试登陆3次
- 当同一用户名3次密码均不正确时，锁定该用户
1 with open('account',encoding='utf8') as f_account, open('lockedlist', 'a+') as f_locked:
2 l = [] #定义用户名验证列表，存放黑名单数据
3 f_locked.seek(0) #"a+"模式打开后，文件位置位于末尾，要遍历文件内容，需要将指针移至文件起始位置
4 for locked_info in f_locked.readlines(): #遍历黑名单
5 l.append(locked_info.strip()) #将黑名单数据添加进列表,注意：需要将文件中的换行符脱掉
6
7 c = [] #定义用户登录名列表，存储用户尝试的登录名
8 count = 1 #登陆次数计数器
9 flag = True #登陆循环控制开关
10 while flag and count < 4:
11 user = input('Please input username:') #输入用户名
12 pwd = input('Please input password:') #输入用户密码
13 if user in l: #用户名在黑名单中
14 print("This user is in blacklist,can't log in!") #打印提示信息
15 continue
16 c.append(user)
17 for info in f_account: #用户名不在黑名单中，遍历用户登陆文件
18 user_name, user_pwd = info.strip().split(',') #将文件中的用户名和登陆密码赋值给判定变量
19 if user == user_name: #用户名符合
20 if pwd == user_pwd: #对应密码符合
21 print('Welcome %s' % user) #打印登陆成功信息
22 flag = False #登陆成功，跳出登陆程序
23 break
24 count += 1 #对应密码不符合，while循环计数器加1
25 break
26 count += 1 #用户名不符合，while循环计数器加1
27 break
28 if count == 4: #如果不同用户名密码输错3次，关闭程序
29 print('More than 3 times wrong!') #打印提示信息
30 if len(c) == 3 and c[0] == c[1] == c[2]: #如果相同用户名密码输错3次，将该用户名加入黑名单，限制登陆
31 print('This user has been locked!')
32 f_locked.write(user+'\n') #将错误3次的用户名写入黑名单，注意，加换行符
