Python - if語句工作不正確

我剛剛開始使用python，並且陷入了一些在我看來應該工作的東西。這是我的第一個代碼，我只是試圖與用戶進行對話。Python - if語句工作不正確

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()

我的問題是，即使我一個否定的答案回答它仍然可以與響應，如果我說是的答覆，如果我切換2左右（所以對於否定答案的代碼是上面的代碼爲正面答案），它總是會回覆，就好像我已經給出了否定的答覆。

來源

2014-01-09 user3178600

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

或

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

會做的伎倆

來源

2014-01-09 17:10:36 mhlester

+1打我吧:) –

您可能也想介紹'str。低' – iCodez

同意。 YEP和YUP錯過了，更不用說其他組合了。 – mhlester

這是因爲條件被解釋爲：

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

嘗試

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

或更簡潔的方式：

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

更簡潔的方式：

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

一個字符串（這裏「是」）轉換成布爾轉換爲true，如果它不是空

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

之後的每個部分或與之前無關。

還考慮使用else或elif而不是兩個相關的if。在測試它們之前儘量降低字符，這樣你就不需要測試了。

來源

2014-01-09 17:13:13 luxcem

這是因爲Python正在評估"Yes"的「真實性」。

你的第一個if語句這樣解釋：

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

你需要比較針對每次yearlikedislike。

試試這樣說：

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

來源

2014-01-09 17:13:47 That1Guy

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

字符串評估爲True。我知道你以爲你說如果像今年一樣喜歡這些東西，就繼續下去。但是，你實際上說的是：

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

你想要的是兩種：

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

或更好：

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

來源

2014-01-09 17:14:00 thumbtackthief

Python - if語句工作不正確

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