python基础-四天(day16)
运算符
product_list = [['phone', 5000],
['book1', 100],
['变形金刚模型', 500],
['小鱼仔一箱', 50],
['伊利牛奶', 100]
]
shopping_cart = {}#字义购物车为一个字典
salary = int(input("input you salary: "))
while True:
index = 0
for product in product_list:
print(index,product)
index +=1
choice = input("请输入要购买的商品编号>>>:").strip()
if choice.isdigit():
choice = int(choice)
if choice >= 0 and choice < len(product_list):
product = product_list[choice]
if product[1] <= salary:
if product[0] in shopping_cart:#判断是否在字典中的方法
shopping_cart[product[0]] [1] +=1
else:
shopping_cart[product[0]] = [product[1],1]
salary -= product[1]
print("添加商品" + product[0] +"到购物车", "你现在的余额为" + str(salary))
else:
print("您的余额不足，产品的价格是" + str(product[1]) + "你还差" + str(product[1] - salary))
else:
print("商品不存在")
elif choice == "q":
print("---------已购买商品列表-------")
id_counter = 1
total_cost = 0
print("id 商品 数量 单价 总价")
for key in shopping_cart:
print("%10s%10s%10s%10s%10s" %(id_counter,
key,
shopping_cart[key][1],
shopping_cart[key][0],
shopping_cart[key][1]*shopping_cart[key][0]))#格式化输出
id_counter +=1
total_cost += shopping_cart[key][1]*shopping_cart[key][0]
print("总花费%s" % (total_cost))
break
else:
print("无此选项")
#######################################################################
if []:
print"yes"
空列表，空字典，空元组，空集合，空字符串，0，布尔值都为假，
算数运算：
比较运算：
赋值运算：
逻辑运算：
成员运算：
身份运算：
位运算：
menu = {
'北京':{
'昌平':{
'沙河':{
'老男孩':100000
}
}
},
'河南':{}
}
exit_flag = False
while not exit_flag:#程序开始打印一级菜单
for key in menu:
print(key)
choice = input(">:").strip()#第1次用户选择
if len(choice) == 0:continue
if choice == 'b': break
if choice == 'q':
exit_flag = True
continue#直接退出不再打印下边的内容
if choice in menu:#省级菜单存在，进入下一级
while not exit_flag:
next_layer = menu[choice]
for key2 in next_layer:
print(key2)
choice2 = input(">>:").strip() # 第2次用户选择
if len(choice2) == 0: continue
if choice2 == 'b': break
if choice2 == 'q':
exit_flag = True
continue
if choice2 in next_layer:#市级菜单存在，进入下一级
while not exit_flag:
next_layer2 = next_layer[choice2]
for key3 in next_layer2:
print(key3)
choice3 = input(">>>:").strip() # 第3次用户选择
if len(choice3) == 0: continue
if choice3 == 'b': break
if choice3 == 'q':
exit_flag = True
continue
if choice3 in next_layer2: # 县级菜单存在，进入下一级
while not exit_flag:
next_layer3 = next_layer2[choice3]
for key4 in next_layer3:
print(key4)
choice4 = input(">>>>:").strip() # 第4次用户选择
if choice4 == 'b':break
if choice4 == 'q':
exit_flag =True
continue
