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Correct me for using generators or tell me in another way

I have a menu item as a key and price as a value. There may exist a combination of items that will be slightly cheaper than individual items. For exa:

menu = {
    ('burger',) : 5.00,
    ('pizza',) : 12.00,
    ('coke',) : 4.00,
    ('macpuff',) : 4.00,
    ('pasta',) : 3.00,
    ('french_fries',) : 2.00,
    ('burger', 'coke', 'french_fries') : 10.00,
    ('pizza', 'coke') : 15.00,
}

Now suppose I ordered several items, then the output will be the minimum quantity of the given order:

I/P >  burger, coke 
O/P >  9      (5.00 + 4.00) 

I/P >  burger, coke, french_fries
O/P >  10.00 

I/P >  pizza, coke, french_fries
O/P >  17.00    (15.00 + 2.00)

here is the code that I tried for all the prices that I will use as generators:

def isSubset(a, b):
    """
        compare two iterable and return true if first is subset of second
    """
    b = list(b)
    if not hasattr(a, '__iter__'):
        a = [a]
    for each in a: 
        try:
            b.remove(each)
        except ValueError:
            return False
    return True

def rest_min_price(order):
    if order:
        for item, price in menu.iteritems():
            if isSubset(order[0], item):
                new_order = order[1:]
                for itm in item:
                    try:
                        new_order.remove(itm)
                    except ValueError:
                        pass
                yield price + rest_min_price(new_order)

but when I ran this, he said an error like:

for each in rest_min_price(order_item):
    print each

TypeError: unsupported operand type(s) for +: 'int' and 'generator'
+4
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3 answers

. - , .

:

class Rest_Menu():
    def __init__(self, menu):
        self.menu = menu
        self.all_price = [] 

    def min_price(self, order, total_price=0):
        """
        Return minm menu price by calculating all possible combination.
        """
        if order:
            for item, price in self.menu.iteritems():
                if isSubset(order[0], item):
                    new_order = [each for each in order]
                    for itm in item:
                        try:
                            new_order.remove(itm)
                        except ValueError:
                            pass
                    self.min_price(new_order, price+total_price)
        else:
            self.all_price.append(total_price)
        return min(self.all_price)

.:)

+5

yield. , yield, . , -, ; next(), . for.

>>> def genDemo(n):
...   while n > 0:
...     yield n
...     n -= 1
... 
>>> 
>>> gd = genDemo(3)
>>> gd
<generator object genDemo at 0x7fce12152820>
>>> gd.next()
3
>>> gd.next()
2
>>> gd.next()
1
>>> gd.next()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
StopIteration
>>> for x in genDemo(3):
...   print x
... 
3
2
1
>>> _

; return.

, ; . , , , , , ..

: , . set.

+2

:

yield price + rest_min_price(new_order)

price int, rest_min_price() generator ( yield, return, ), TypeError.

:

for item in rest_min_price(order_item):
    # process the item
    # yield result with price
0

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