大家好,我有这个代码,它可以打印出该项目的最低成本和餐厅 ID。顾客不想光顾多家餐馆。因此,例如,如果他要求“A,B”,那么代码应该打印提供这两者的商店,而不是将用户需求分散在不同的餐厅(即使某些餐厅提供便宜的价格)。
另外,如果假设用户要汉堡。那么如果某个餐厅“X”以 4 美元的价格提供“汉堡”,而另一家餐厅“Y”以 3 美元的价格提供“汉堡+金枪鱼+ bean 腐”,那么我们会告诉用户去餐厅“Y”,即使除了用户要求的“汉堡”之外还有额外的元素,但我们很乐意为他们提供额外的元素,只要价格便宜。
一切都很好,但代码在两个输入文件上的行为不同(在 input.csv 上失败,但在 input-2.csv 上运行),它们具有相同的格式,它为一个提供正确的输出,而为另一个提供失败。这是我需要你帮助修复的唯一一个微小错误。请帮助我,我想我已经碰壁了,无法思考超越这一切。
def build_shops(shop_text):
shops = {}
for item_info in shop_text:
shop_id,cost,items = item_info.replace('\n', '').split(',')
cost = float(cost)
items = items.split('+')
if shop_id not in shops:
shops[shop_id] = {}
shop_dict = shops[shop_id]
for item in items:
if item not in shop_dict:
shop_dict[item] = []
shop_dict[item].append([cost,items])
return shops
def solve_one_shop(shop, items):
if len(items) == 0:
return [0.0, []]
all_possible = []
first_item = items[0]
if first_item in shop:
print "SHOP",shop.get(first_item)
for (price,combo) in shop[first_item]:
#print "items,combo=",items,combo
sub_set = [x for x in items if x not in combo]
#print "sub_set=",sub_set
price_sub_set,solution = solve_one_shop(shop, sub_set)
solution.append([price,combo])
all_possible.append([price+price_sub_set, solution])
cheapest = min(all_possible, key=(lambda x: x[0]))
return cheapest
def solver(input_data, required_items):
shops = build_shops(input_data)
#print shops
result_all_shops = []
for shop_id,shop_info in shops.iteritems():
(price, solution) = solve_one_shop(shop_info, required_items)
result_all_shops.append([shop_id, price, solution])
shop_id,total_price,solution = min(result_all_shops, key=(lambda x: x[1]))
print('SHOP_ID=%s' % shop_id)
sln_str = [','.join(items)+'(%0.2f)'%price for (price,items) in solution]
sln_str = '+'.join(sln_str)
print(sln_str + ' = %0.2f' % total_price)
shop_text = open('input-1.csv','rb')
solver(shop_text,['burger'])
=====input-1.csv=====restaurant_id、价格、商品
1,2.00,burger
1,1.25,tofulog
1,2.00,tofulog
1,1.00,chef_salad
1,1.00,A+B
1,1.50,A+CCC
1,2.50,A
2,3.00,A
2,1.00,B
2,1.20,CCC
2,1.25,D
====输出和错误====:
{'1': {'A': [[1.0, ['A', 'B']], [1.5, ['A', 'CCC']], [2.5, ['A', 'D']]], 'B': [[1.0, ['A', 'B']]], 'D': [[2.5, ['A', 'D']]], 'chef_salad': [[1.0, ['chef_salad']]], 'burger': [[2.0, ['burger']]], 'tofulog': [[1.25, ['tofulog']], [2.0, ['tofulog']]], 'CCC': [[1.5, ['A', 'CCC']]]}, '2': {'A': [[3.0, ['A']]], 'B': [[1.0, ['B']]], 'D': [[1.25, ['D']]], 'CCC': [[1.2, ['CCC']]]}}
SHOP [[2.0, ['burger']]]
Traceback (most recent call last):
File "work.py", line 55, in <module>
solver(shop_text,['burger'])
File "work.py", line 43, in solver
(price, solution) = solve_one_shop(shop_info, required_items)
File "work.py", line 26, in solve_one_shop
for (price,combo) in shop[first_item]:
KeyError: 'burger'
如果我在 input-2.csv 上运行相同的代码,并查询solver(shop_text,['A','CCC']),我会得到正确的结果
======input-2.csv======
1,2.00,A
1,1.25,B
1,2.00,B
1,1.00,A
1,1.00,A+B
1,1.50,A+CCC
1,2.50,A+D
2,3.00,A
2,1.00,B
2,1.20,CCC
2,1.25,D
==========输出====
{'1': {'A': [[2.0, ['A']], [1.0, ['A']], [1.0, ['A', 'B']], [1.5, ['A', 'CCC']], [2.5, ['A', 'D']]], 'B': [[1.25, ['B']], [2.0, ['B']], [1.0, ['A', 'B']]], 'D': [[2.5, ['A', 'D']]], 'CCC': [[1.5, ['A', 'CCC']]]}, '2': {'A': [[3.0, ['A']]], 'B': [[1.0, ['B']]], 'D': [[1.25, ['D']]], 'CCC': [[1.2, ['CCC']]]}}
SHOP [[2.0, ['A']], [1.0, ['A']], [1.0, ['A', 'B']], [1.5, ['A', 'CCC']], [2.5, ['A', 'D']]]
SHOP [[1.5, ['A', 'CCC']]]
SHOP [[1.5, ['A', 'CCC']]]
SHOP [[1.5, ['A', 'CCC']]]
SHOP [[1.5, ['A', 'CCC']]]
SHOP [[3.0, ['A']]]
SHOP [[1.2, ['CCC']]]
SHOP_ID=1
A,CCC(1.50) = 1.50
最佳答案
如果这样做,您可以找出错误:
在您的 solve_one_shop
方法中,在 first_item = items[0]
行之后打印字典 shop
。这样做将打印出:
{'A': [[3.0, ['A']]], 'B': [[1.0, ['B']]], 'D': [[1.25, ['D' ']]],'CCC':[[1.2,['CCC']]]}
因此,burger
不是其键之一,因此它会抛出 KeyError
添加这一行:
2,1.25,汉堡
添加到 input.csv
文件的末尾,并且您的代码可以正常工作。
在 try except block 中从 shop
字典中读取值,以处理项目可能不存在的情况。
注意:
在您的方法 build_shops
中,该行:
shop_id,cost,items = item_info.replace('\n', '').split(',')
虽然去掉了换行符,但并没有去掉回车符。要解决此问题,请执行以下操作:
shop_id,cost,items = item_info.replace('\n', '').replace('\r', '').split(',')
希望这有帮助。
关于python 代码在一个文件上有效,但在其他文件上失败,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/22646090/