这个python程序怎么了？

Question

我正在尝试做一个Derp模拟器小游戏的东西'因为我很无聊，和一个问题突然出现，如果你试图购买猫粮它添加到库存猫粮，但不添加到猫粮计数，它不会带走钱。我使用一个单独的模块比实际的商店游戏文件，所以如果有人可以尝试，并找到什么是错的，我将不胜感激

我这样调用shop函数： shop(inv, balance, catfood, liqpota)

车间代码：

from functions import *
def shop(inv, balance, catfood, liqpota):
while True:
    print "Welcome to the shop."
    print "-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-"
    print "( To purchase an item; enter the letter of the item. )"
    print "( If you want to exit; enter 'back'. )"
    print "A] $5 Cat Food - 'Not Just For Cats'"
    print "B] $7 Liquified Potatoes - 'Who Would Want These?'"
    print
    com = raw_input("Purchase: ")
    divider()
    if com == "back" or com == "Back":
        break
    elif com == "a" or com == "A":
        if "Cat Food" in inv:
            if balance < 7:
                print "You have insufficient funds."
            elif balance > 7 or balance == 7:
                catfood = catfood + 1
                balance = balance - 7
                print "Purcahse succcessful."
                return catfood
                return liqpota
        if not "Cat Food" in inv:
            if balance < 7:
                print "You have insufficient funds."
            elif balance > 7 or balance == 7:
                catfood = catfood + 1
                balance = balance - 7
                inv.append("Cat Food")
                print "Purchase successful."
                return catfood
                return liqpota
    elif com == "b" or com == "B":
        print "WIP"
        break
    else:
        print "Invalid Item/Command."
    divider()

主代码：（库存部分）

elif com == "inventory" or com == "Inventory":
    tmp_invnum = 1
    print "Cat Food = " + str(catfood)
    print "Liquified Potatoes = " + str(liqpota)
    print
    for invf in inv:
        print str(tmp_invnum) + "] " + invf
        tmp_invnum += 1

Answer 1

第二个return语句（return liqpota）永远不会执行，因为函数在遇到第一个返回时结束。您可以在一条语句中返回所有值，并在函数调用时将它们解包。我在下面举了一个例子

def divider():
    print '*' * 80

def shop(inv, balance, catfood, liqpota):
    while True:
        print "Welcome to the shop."
        print "-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-"
        print "( To purchase an item; enter the letter of the item. )"
        print "( If you want to exit; enter 'back'. )"
        print "A] $5 Cat Food - 'Not Just For Cats'"
        print "B] $7 Liquified Potatoes - 'Who Would Want These?'"
        print
        com = raw_input("Purchase: ")
        divider()
        if com == "back" or com == "Back":
            break
        elif com == "a" or com == "A":
            if "Cat Food" in inv:
                if balance < 7:
                    print "You have insufficient funds."
                elif balance > 7 or balance == 7:
                    catfood = catfood + 1
                    balance = balance - 7
                    print "Purcahse succcessful."
                    # return all four variables at once
                    return (catfood,liqpota,inv,balance)

            if not "Cat Food" in inv:
                if balance < 7:
                    print "You have insufficient funds."
                elif balance > 7 or balance == 7:
                    catfood = catfood + 1
                    balance = balance - 7
                    inv.append("Cat Food")
                    print "Purchase successful."
                    # return all four variables at once
                    return (catfood,liqpota,inv,balance)

        elif com == "b" or com == "B":
            print "WIP"
            break
        else:
            print "Invalid Item/Command."

        divider()

    return (catfood,liqpota,inv,balance)

catfood = 0
liquified_potatoes = 0
balance = 30
inv = []

print 'catfood %s potatoes %s inventory %s balance %s' % (catfood,liquified_potatoes,inv,balance)

catfood, liquified_potatoes, inv, balance = shop(inv, balance, catfood, liquified_potatoes)        

print 'catfood %s potatoes %s inventory %s balance %s' % (catfood,liquified_potatoes,inv,balance)