我应该使用全局变量还是在此示例中还有其他选项？

Question

我有一个有关使用全局变量的问题。我有这样的情况：我必须循环穿过森林，然后穿过蜂巢才能找到蜜蜂，然后蜜蜂应该将蜂蜜存放在Honey_jar中。

我可以使用这种方法：

class HoneyJar:
    def deposit_honey(self, bee):
        print(f"Honey desposited by {bee}")


def loop_bees(nest):
    bees = [1, 2, 3, 4]  # Assume i have bees from some nest
    for bee in bees:
        honey_jar = HoneyJar()
        honey_jar.deposit_honey(bee)


def loop_hives(forest):
    bee_nests = [1, 2, 3, 4]  # Assume i have bee_nest from some forest
    for bee_nest in bee_nests:
        loop_bees(bee_nest)


def main():
    forests = ['Amazon', 'Madagascar']
    for forest in forests:
        loop_hives(forest)


main()

但这意味着我在每个循环中都会创建Honeyjar实例。

我可以通过在顶级创建Honey_jar并将其用作全局变量来解决这个问题。

honey_jar = HoneyJar()

def loop_bees(nest):
    global honey_jar

    bees = [1, 2, 3, 4]  # Assume I have bees from some nest
    for bee in bees:
        honey_jar.deposit_honey(bee)

什么会更好？

Answer 1

正如马蒂亚斯（Matthias）所建议的那样，您应该在主机中使用类似的东西。
第一件事是在主机中创建一个honeyjar的一个实例，
然后传递对其他方法的引用。

def main():
    forests = ['Amazon', 'Madagascar']
    honey_jar = HoneyJar() # instantiate HoneyJar once here
    for forest in forests:
       loop_hives(forest=forest, jar=honey_jar) # then pass it to the other methods

而您的loop_hives和loop_bees将是：

def loop_bees(nest, jar):
    bees = [1, 2, 3, 4]  # Assume i have bees from some nest
    for bee in bees:
        jar.deposit_honey(bee)


def loop_hives(forest, jar):
    bee_nests = [1, 2, 3, 4]  # Assume i have bee_nest from some forest
    for bee_nest in bee_nests:
        loop_bees(bee_nest, jar)