“或"Python 中的条件问题

2022-01-20 00:00:00 python conditional-statements conditional-operator

问题描述

我正在学习 Python，但遇到了一点问题.在我正在学习的课程中看到类似的东西后想出了这个简短的脚本.我之前成功地使用了或"和如果"(这里没有显示太多).出于某种原因，我似乎无法正常工作:

I'm learning Python and I'm having a little bit of a problem. Came up with this short script after seeing something similar in a course I'm taking. I've used "or" with "if" before with success (it doesn't show much here). For some reason I can't seem to get this working:

test = raw_input("It's the flying circus! Cool animals but which is the best?")
x = test.lower()

if x == "monkey" or "monkeys":
    print "You're right, they are awesome!!"
elif x != "monkey" or "monkeys":
    print "I'm sorry, you're incorrect.", x[0].upper() + x[1:], "is not the right animal."

但这很好用:

test = raw_input("It's the flying circus! Cool animals but which is the best?")
x = test.lower()

if x == "monkey":
    print "You're right, they are awesome!!"
elif x != "monkey":
    print "I'm sorry, you're incorrect.", x[0].upper() + x[1:], "is not the right animal."

可能 or 条件不适合这里.但我已经尝试过，等等.我希望有一种方法可以让这个接受猴子或猴子，其他一切都会触发 elif.

Probably the or conditional does not fit here. But I've tried and, etc. I'd love a way to make this accept monkey or monkeys and everything else triggers the elif.

解决方案

大多数编程语言中的布尔表达式不遵循与英语相同的语法规则.您必须对每个字符串进行单独比较，并将它们与 或 连接起来:

Boolean expressions in most programming languages don't follow the same grammar rules as English. You have to do separate comparisons with each string, and connect them with or:

if x == "monkey" or x == "monkeys":
    print "You're right, they are awesome!!"
else:
    print "I'm sorry, you're incorrect.", x[0].upper() + x[1:], "is not the right animal."

你不需要对不正确的情况进行测试，只需使用else.但如果你这样做了，那就是:

You don't need to do the test for the incorrect case, just use else. But if you did, it would be:

elif x != "monkey" and x != "monkeys"

你还记得在逻辑课上学习过德摩根定律吗?他们解释了如何反转连词或析取词.

Do you remember learning about deMorgan's Laws in logic class? They explain how to invert a conjunction or disjunction.

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