Python - if语句工作不正确

我刚刚开始使用python，并且陷入了一些在我看来应该工作的东西。这是我的第一个代码，我只是试图与用户进行对话。Python - if语句工作不正确

year = input("What year are you in school? ") 
yearlikedislike = input("Do you like it at school? ") 
if (yearlikedislike == "yes" or "Yes" or "YES" or "yep" or "yup" or "Yep" or "Yup"): 
    print("What's so good about year " + year, "? ") 
    input("")  
    print("That's good!") 
    time.sleep(1) 
    endinput = input("I have to go now. See you later! ") 
    exit() 
if (yearlikedislike == "no" or "No" or "nope" or "Nope" or "NOPE"): 
    print("What's so bad about year " + year, "?") 
    input("") 
    time.sleep(1) 
    print("Well that's not very good at all") 
    time.sleep(1) 
    endinput = input("I have to go now. See you later! ") 
    time.sleep(1) 
    exit()

我的问题是，即使我一个否定的答案回答它仍然可以与响应，如果我说是的答复，如果我切换2左右（所以对于否定答案的代码是上面的代码为正面答案），它总是会回复，就好像我已经给出了否定的答复。

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2014-01-09 user3178600

if yearlikedislike in ("yes", "Yes", "YES", "yep", "yup", "Yep", "Yup"):

或

if yearlikedislike.lower() in ("yes","yep","yup"):

会做的伎俩

来源

2014-01-09 17:10:36 mhlester

+1打我吧:) –

您可能也想介绍'str。低' – iCodez

同意。 YEP和YUP错过了，更不用说其他组合了。 – mhlester

这是因为条件被解释为：

if(yearlikedislike == "yes" or "Yes" == True or "YES" == True #...

尝试

if(yearlikedislike == "yes" or yearlikedislike == "Yes" or yearlikedislike == "YES"#...

或更简洁的方式：

if(yearlikedislike in ("yes", "Yes", "YES", #...

更简洁的方式：

if(yearlikedislike.lower() in ("yes", "yup", #...

一个字符串（这里“是”）转换成布尔转换为true，如果它不是空

>>> bool("") 
False 
>>> bool("0") 
True 
>>> bool("No") 
True

之后的每个部分或与之前无关。

还考虑使用else或elif而不是两个相关的if。在测试它们之前尽量降低字符，这样你就不需要测试了。

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2014-01-09 17:13:13 luxcem

这是因为Python正在评估"Yes"的“真实性”。

你的第一个if语句这样解释：

if the variable "yearlikedislike" equals "yes" or the string literal "Yes" is True (or "truthy"), do something

你需要比较针对每次yearlikedislike。

试试这样说：

if yearlikedislike in ("yes", "Yes", "YES", "yep", "yup", "Yep", "Yup"): 
    #do something

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2014-01-09 17:13:47 That1Guy

if (yearlikedislike == "yes" or "Yes" or "YES" or "yep" or "yup" or "Yep" or "Yup"):

字符串评估为True。我知道你以为你说如果像今年一样喜欢这些东西，就继续下去。但是，你实际上说的是：

if yearlikedislike equals "yes", or if "Yes" exists (which it does), or "YES" exists, etc:

你想要的是两种：

if (yearlikedislike == "yes" or yearlikedislike == "Yes" or yearlikedislike == "YES")

或更好：

yearlikedislike in ("yes", "Yes", "YES", "yep", "yup", "Yep", "Yup")

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2014-01-09 17:14:00 thumbtackthief

Python - if语句工作不正确

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