Question

将变量prize设置为None的原因是什么？

def which_prize2(points):

    prize = None
    if points <= 50:
        prize = "a wooden rabbit"
    elif 151 <= points <= 180:
        prize = "a wafer-thin mint"
    elif points >= 181:
        prize = "a penguin"

    if prize:
        return "Congratulations! You have won " + prize + "!"
    else:
        return "Oh dear, no prize this time."

Answer 1

如果变量NameError不存在，则会引发prize例外变量奖金是设置为None还是""（空字符串）还是0并不重要，因为所有这些值在Python中都是假的。

在此特定示例中，奖金设置为None，因为在if / else签入时它将退出。
即使这个if / elif块不创建变量奖品，也会在此块之前创建变量奖品：

if points <= 50:
    prize = "a wooden rabbit"
elif 151 <= points <= 180:
    prize = "a wafer-thin mint"
elif points >= 181:
    prize = "a penguin"

Python，将变量设置为None

1 个答案: